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Avalanche Accidents in Canada. II. A Selection of Case Histories of Accidents 1943 to 1978 Stethem, C. J.; Schaerer, P. A.
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Paper (National Research Council of Canada. Division of Building Research); Issue 926
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. . ' r..
--. .- -. . NATIONAL RESEARCH COUNCIL OF CANADA
DIVISION OF BUILDING RESEARCH
AVALANCHE ACCIDENTS IN CANADA
11. A SELECTION OF CASE HISTORIES
OF ACCIDENTS 1943 TO 1978
b Y C.J. Stethem and P.A. Schaerer
DBR Paper No. 926
of the
Division of Building Research
OTTAWA, July 1980 AVALANCHE ACCIDENTS IN CANADA 11. A SELECTION OF CASE HISTORIES OF ACCIDENTS 1943 TO 1978 by C.J. Stethem and P.A. Schaerer
ABSTRACT
Case histories are presented of avalanche accidents in Canada that resulted in death or injury. A first volume describing accidents between 1955 and 1976 was published earlier (NRCC 17292). The present publication contains cases from the winters 1976 to 1978 and a few selected ones from earlier years. They contain a description of the weather, snow conditions, circumstances leading to the accident, the event, and the rescue operation.
ACCIDENTS CAUS~SPAR LES AVALANCHES AU CANADA
11. CHOIX DE CAS DOCUMENT~SD'ACCIDENTS DE 1943 1978 par C.J. Stethem and P.A. Schaerer
Des cas dlaccidents caus6s par des avalanches au Canada ayant provoqug la mort ou des blessures sont pr6sentGs. Un premier volume dgcrit les accidents qui se sont produits entre 1955 et 1976 a 6t6 publigs plus t6t (NRCC 17292). Cette publication contient les cas des hivers de 1976 5 1978 et certains autres cas choisis dans le rgpgrtoire des ann6es pr6cGdentes. Les cas documenti% contiennent une description de la tempgrature, des conditions de la neige, des circonstances qui ont conduit 2 l'accident, l'accident comme tel, et 110p6ration de sauvetage. FOREWORD
The objective of the avalanche research program of the Division of Building Resea~chof the National Research Council is to develop and make available information about snow avalanches and protection from them. In partial fulfillment of this objective, case histories of accidents were collected that either resulted in death, injury, or property damage or have educational value. A first volume describing 40 accidents between 1955 and 1976 was published earlier (NRCC 17292). The present publication contains the accident cases of the two winters between 1976 and 1978 and some additional ones from earlier years.
The case histories presented in this report were collected by Mr. Chris Stethem, working on Contract OSS77-08171 with the National Research Council of Canada. Mr. Stethem obtained the information from published reports, from files of agencies and through interviews with persons who were either eyewitnesses to the accident or involved in the rescue operation.
The reader will notice an increase in the amount of information concerning individual accidents towards the end of this report. The most recent cases are well documented with weather, snowpack and avalanche observations. This is a reflection of a growth in interest and knowledge of personnel working in avalanche areas, which in some part, is the result of education in which the National Research Council played an important role by developing avalanche course programs, assisting in instruction and through publications such as this one.
The compilation of accident case histories will continue, and publication of a further volume containing the numerous accidents and destructive avalanches of February 1979 is anticipated. Furthermore it is planned to collect statistics about the numerous encounters that have not resulted in death, injury, or serious property damage. The assistance of individuals and agencies who make available information is gratefully acknowledged, and it is expected that the same co-operation will continue.
Ottawa C.B. Crawford July 1980 Director, DBR/NRC ACKNOWLEDGEMENT
The National Research Council wishes to express its thanks to the following agencies, organizations, and individuals who have contributed information.
Apex Alpine Recreations Ltd. Atmospheric Environment Service Canada British Columbia Ministry of Transportation and Highways
British Columbia Ministry of Lands, Parks and Housing British Columbia Ministry of the Attorney-General Canadian Mountain Holidays
Canadian National Railways
Garibaldi Lifts Limited
Ocean Falls Corporation Parks Canada Suret6 de Quebec Workers Compensation Board of British Columbia B. Geisler W. Jenkins W. Kleinschrot R. Neville C. Sadleir LIST OF THE ACCIDENTS
11 February Kwinitsa Workmen killed, Construction camp destroyed 23 February Fraser Canyon Person on road killed 14 January Fraser Canyon Workman killed 27 March Seymour Inlet Workman killed 23 February Woodbury Creek Person on road killed 24 March McGillivray Pass Skiers killed 7 April Torbit Mine Workman killed 19 July Mt. Garibaldi Mountain climber killed 21 January Silver Star Skier killed 13 January Ocean Falls Persons in buildings killed, buildings destroyed 11 August Mt. St. Elias Mountain climbers killed 14 March Nine Mile Mountain Snowmobile operator killed 13 February Westcastle Workman injured 11 June Mt. Fisher Mountain climbers injured 11 December Sunshine Village Skier buried 12 December Chancellor Peak Mountain climbers killed 28 December Tadoussac Snowmobile operator killed 15 February Parker Ridge Skier killed 16 March Diana Lake Skier killed 17 March Bugaboo Skiers killed 19 March Bow Peak Mountain climber killed 21 March Apex Mountain Skier killed 27 March Quartz Ridge Skier killed 30 March Lake Louise Skier killed 7 September Mt. Athabasca Mountain climbers injured 9 October President's Col Mountain climber killed 8 March Whistler Mountain Skiers buried PREFACE
The list of accidents described in this publication is a reflection of the change in activities in the mountains of Western Canada and the shift in the type of involvements with avalanches. In the years before 1960 avalanche accidents occurred mainly on roads and in work areas such as construction, mining and logging, but when recreation in the mountains became more popular the number of acctdents involving skiers and mountain climbers increased. On the average seven people per year have died in avalanches in Canada between 1970 and 1978, the period when accurate records were maintained. With 13 deaths the winter of 1976-1977 was above average, and all 13 persons were involved in recreational activities.
Three important conclusions can be drawn from features common to several cases.
1. The time for survival of persons completely encased in the snow is very short. This means that live rescue depends on the quick action of the accident witnesses who must immediately search likely areas of burial. Obviously rescue transceivers and probes assist greatly in locating buried victims, and shovels carried by the rescuers are essential for a quick recovery.
2. Several persons on roads and on skis have died when a second avalanche ran after the first one. For this reason danger from later avalanches and proper safety measures must be considered in rescue and snow removal operations. 3. Some skiers were caught in avalanches on slopes that had been treated with artillery fire a short time before. When a deep slab instability exists such slopes may be considered safe only when avalanches were actually observed and the unstable snow removed. KWINITSA, SKEENA RIVER VALLEY, B.C. 11 FEBRUARY 1943
Three men killed, eleven injured, several buildings destroyed
WEATHER
Observations at Terrace Airport, 60 m ASL
Temperature Precipitation Oc
Date Max Min mm
7 February 4.5 3.0 45
8 February 3.5 0.5 30
9 February 4.0 -0.5 5.5
10 February 0.5 -6.5
11 February 0 -3.5 2.5
Experience has shown that warm moisture laden fronts usually arrive earlier and deposit more snow at the accident site than at Terrace. On 12 and 13 February a total of 51 mm of precipitation was recorded at Terrace Airport.
SITUATION
The accident site was at McLean Point on the shore of the Skeena River 85 km west of Terrace. A construction camp to house workmen building the highway from Terrace to Prince Rupert was located beside the railway tracks in the runout zone of a large avalanche gully.
In the early winter of 1942-43 officials of the Canadian National Railway visited the camp and warned the superintendent of the avalanche danger. In January 1943 an avalanche descended the gully and blocked about 30 m of the railway track but did not reach the camp. A railroad engineer again visited the camp and told of a snowshed that had been destroyed at the same site about 10 years earlier.
By early February the avalanche hazard had become the central topic of discussion among the 200 men working in the camp. During the second week of February a storm raged in the area. Most of the precipitation fell as rain at the lower elevations, but on the night of 10 February snow was deposited at the camp.
ACCIDENT SUMMARY
At about 0730 h on 11 February most of the men had finished break- fast and were preparing to leave for work, when suddenly a rumbling was heard. An avalanche swept down the gully and struck the camp carrying away two small bunkhouses and the first aid shack. Several men were caught. One of them who had been standing by a 14-ton locomotive was crushed by the moving snow and debris, and another one close-by was swept away and buried. Those who escaped the avalanche aided the injured, moving them to the remaining bunkhouses and then, because other avalanches seemed imminent, to the patrolmen's shack at Telegraph Point, 2 km west. Other survivors remained behind and searched for those still missing.
As the injured men were being moved a second slide struck, and destroyed the two remaining bunkhouses. Several men were partially buried and some were carried into the river. Only the office at the east end of the camp and the commissary at the west end remained standing. About twenty minutes later, when the remaining men were moving to safety, a third avalanche struck destroying the office.
RESCUE
A westbound passenger train arrived at the site about one and one half hours after the first avalanche. Two doctors on board crossed the avalanche deposit to aid the injured.
Two men remained missing and several were incapacitated with injuries. Word reached Prince Rupert by telegraph and a hospital train was dispatched to the site the following morning. During the return trip one man died of injuries; eleven were hospitalized.
On 15 February the body of one of the missing men was located, but the other one was never found. Presumably it was carried away by the river. A few days later the camp was rebuilt in a safe position at Telegraph Point.
AVALANCHE
The McLean Point avalanche fell some 1000 m vertically onto the railway and highway. The starting zone of southerly aspect was in a steep, wide granite gully covered with mixed sparse vegetation. The avalanche track was a steep sided gully with an average gradient of 34O. Approximately 100 m above the railway and the highway the gully opened into an alluvial fan covered with shrubs. COMMENT
The Skeena River Valley between Terrace and Prince Rupert is one of the most active avalanche areas in British Columbia where avalanches frequently block the railway and the highway. Considering the frequent avalanches and the heavy annual snowfall in the area it should be obvious even to a layman that the steep gully at McLean Point would be an avalanche track. It is hard to believe that a construction camp was built there and maintained during the winter. The reason was probably that over a distance of several kilometers there is little space between the steep mountain and the river, therefore the alluvial fan at the toe of McLean Mountain was particularly attractive.
The railway staff was aware of the avalanche hazard, because a snow shed had once covered the tracks at this site and was destroyed 18 April 1933. Unfortunately the managers of the highway construction company did not heed the warnings. Their excuse was that they had planned to complete the job before the winter, but obviously they gambled heavily and lost when it was not.
This case proves that several destructive avalanches may run in the same path during the same storm and often within a short time of each other. For this reason the danger from further avalanches must be a primary concern for the leader of any avalanche rescue mission. Figure 1 View of the avalanche site in 1976 showing the railway and the highway at the side of the river. (Photo courtesy British Columbia Ministry of Transportation and Highways). FRASER CANYON, B.C. 23 FEBRUARY 1949
! One truck driver killed
A truck convoy left Boston Bar late on the afternoon of 23 February in an attempt to negotiate the snowbound Fraser Canyon highway south towards Vancouver. Shortly before 1900 h the convoy was stopped at the Hoodoo curve by a small avalanche that had been partially cleared by bulldozer. The driver of a truck that had become stuck in the deposited snow had begun to mount tire chains when a larger avalanche struck. When it stopped only the roof line of the truck remained visible and the driver had disappeared in the snow. The other drivers in the convoy and the highway crew began a search. Another avalanche struck and engulfed five of the rescuers sweeping them well down the slope towards the river. When the remaining rescuers began a search for these men a third avalanche struck burying several men to their knees. Miraculously all persons were found alive with theexceptionof the first buried driver. His body was located at the rear of his truck the following day. FRASER CANYON, B.C. 14 JANUARY 1 95 0
One railway employee killed
Severe storms raged in the Fraser Canyon early in January 1950 causing three closures during a three-week period. A Canadian National Railway snow plow was working south of Boston Bar on 14 January. The crew parked the plow 13 km south of Boston Bar and returned north with the engine to pick up some other equipment but the foreman remained with the plow. While the crew was gone an avalanche containing both snow and rock struck the plow. It was carried part way down the embankment towards the river, and the foreman was swept into the river. When the crew returned the foreman could not be found. The cause of the avalanche was attributed to rain which weakened the snow at the canyon walls. SEYMOUR INLET 27 MARCH 1955
One logger killed, one injured
LOCATION
I Seymour Inlet is on the Pacific Coast of British Columbia, 350 km I northwest of Vancouver and has a wet, maritime climate.
WEATHER
Moderate temperatures and rain prevailed at the accident site on 27 March. Thaw persisted and the snowpack was water-saturated.
ACCIDENT
A crew was yarding logs on a steep slope above Seymour Inlet. On one turn of the yarder a stump rolled over about 250 m upslope from the engine's location. During the next turn a log which was being drawn caught the stump and dislodged it. The stump, the snow surrounding it, and some of the surface vegetation began to move slowly down the slope, then after falling onto steeper terrain above the yarder rapidly increased in volume and speed.
The signalman had called out when the motion began. He himself was unable to escape and was caught near the top of the avalanche, but after a ride of about 60 m was left behind the moving snow. Two workers in the landing area saw the start of the avalanche and ran clear of it. The yarder engineer noticed it too late, and together with the donkey engine was engulfed in the moving snow and debris and swept into the inlet. When the avalanche stopped the only things visible were broken logs and other debris on the surface of the water.
1 RESCUE After the avalanche had stopped the unscathed workers began a surface search and found the signalman near the top of the avalanche path. He had sustained a broken arm and cracked ribs. His companions carried him on a stretcher from the slope. There was no sign of the engineer, and'continuing debris movement at the edges of the avalanche path made a search difficult. Later searches on the same day revealed no sign of the engineer and the deep water in the inlet made diving unfeasible. The body was never found. The injured signalman was flown by seaplane to the hospital at Alert Bay. AVALANCHE The avalanche was triggered by the motion of the stump in the water-saturated snowpack. The loose snow avalanche started on a slope with an incline of about 10" at an elevation of about 600 m. For the first 30 m it moved slowly with a width of about 8 m. After falling over a transition onto an approximately 25" slope the avalanche quickly gained momentum and volume, and expanded to a maximum width of 120 m. The moving snow stripped the soil and vegetation down to the granite bedrock. COMMENT The engineer would have had to run about 50 m to safety. Probably he could have escaped if he had received a warning when the avalanche started. Unfortunately due to the noise of the engine he could hear neither a warning nor the avalanche until it was too late. The avalanche carried the heavy logging equipment down the slope and splintered logs with diameters greater than 1 m. This illustrates the destructive force of the heavy, wet moving snow mixed with debris.
TAIL BLOCK /
X POSITION OF SIGNALMAN PRIOR TO AVALANCHE @ POSITION OF SIGNALMAN AFTER AVALANCHE + POSITION OF ENGINEER PRIOR TO AVALANCHE
Figure 2 Sketch of the accident site at Seymour Inlet -8- WOODBURY CREEK, KASLO, B.C. 23 FEBRUARY 1957
Person on road killed
LOCAT ION
The accident site is located about 18 km south of Kaslo on the shores of Kootenay Lake.
WEATHER
Observations at Kaslo climate station 585 m ASL
Temperature Precipitation
Oc
Date Max Min mm
20 February - 5 - 17
21 February -6.5 -18
22 February - 8 -15 13
23 February 5 -10.5 2 5
A storm raged from 22 to 25 February depositing deep snow in the Nelson-Kaslo area.
ACCIDENT SUMMARY
The Anglican minister from New Denver drove from Nelson to Kaslo on Saturday afternoon, 23 February. A short distance south of Woodbury Creek he was stopped by a small avalanche which had crossed the road. He got out of his car and began to shovel a path through the snow. A second car stopped and the driver, a local resident, joined the minister advising him to watch for further avalanches.
Suddenly a second, larger avalanche came from the bluffs above the road. The second driver shouted a warning and ran clear of the avalanche's path, but the minister, running in the opposite direction, was engulfed by the avalanche. After the snow had settled there was no sign of him. RESCUE
The second driver looking over the deposited snow was unable to locate the minister. He sent his wife, who had been waiting in their car, for help and continued the search. About one hour after the accident rescuers found the minister covered by 1 to 2 m of snow, about 12 m below the road. No sign of life was evident..
AVALANCHE
The storm continued and a third avalanche ran in the same location on the following day. The fatal avalanche was confined to a narrow gulley in steep, rocky bluffs above the road. The vertical run of the avalanche was probably less than 100 m, and a length of about 25 m of road was covered by snow up to 2 m deep.
COMMENT
As in other cases the recurrent nature of an avalanche path proved to be the cause of the fatality. The minister, who served both New Denver and Kaslo, frequently travelled over the avalanche-prone road between the two towns was aware of the danger. His precautions usually included obtaining advice from the Department of Highways about the avalanche hazards before he made the trip, but he neglected to do so on the day of the accident because he travelled over another road.
At the time of the accident the road was narrow, winding along the shores of Kootenay Lake, and winter travel was hazardous. Since then the road has been relocated on a new, wider bench about 35 m above the lake. The reconstruction seems to have eliminated the avalanche problems at this site. McGILLIVRAY PASS, B.C. 24 MARCH 1959
Two skiers killed
McGillivray Pass is on the east side of the Pacific Coast Mountains between Anderson Lake and Bralorne, B.C. The summit, 1860 m high, is about 23 km SE of Bralorne.
WEATHER
During the week prior to 24 March 1959 approximately 45 cm of new snow accumulated in the McGillivray Pass area. March 24 was a clear, sunny day during which the temperature rose above 0°C and the top 15 cm of snow became heavy and moist.
ACCIDENT SUMMARY
I The accident itself was unobserved. At approximately 1300 h a I young Bralorne couple met a friend while skiing towards McGillivray Pass. They intended to survey some land in the summit area, thinking of a possible purchase. Their friend, considering the new snow and the high temperature, warned them of the avalanche hazard.
Later that afternoon the friend, while skiing at Telephone Ridge on the southwest side of the valley, noted a fresh avalanche deposit on the opposite side of the valley just southeast of the pass. Ski tracks led to the deposit but none left it. When he approached the avalanche for a closer look he realized that his friends had been caught in it. RESCUE
I The skier searched the deposition, digging and probing with ski poles at random but found nothing. He then skied back to his cabin some 3.5 km northwest of the site and telephoned to Bralorne for help.
The Royal Canadian Mounted Police in Bralorne received the report at 1745 h and gathered residents into a search party. They travelled a few miles by jeep, then by skis and snowshoes, arriving at the accident site several hours later. The rescuers searched throughout the night using scaling bars for probes and shovels for digging through the deposition. Avalanche guards had been posted to warn searchers of any further activity. On 25 March the search continued in temperatures below O"C with cloudy skies and light snowfall. At 1530 h on 25 March the first body was located; the second was located at 1035 h on 26 March. Both had died of suffocation. The valley sides around McGillivray Pass contain numerous avalanche paths. The accident site was about 0.8 km southeast of the summit and 100 m above the valley floor on a slope with a SSW exposure, The avalanche path was approximately 50 m wide, 200 m long and its snow was deposited to a depth varying from 1.2 to 2.5 m. Deep new snowfall, followed by high temperatures and radiant heat from the sun on the southerly slope led to the unstable snow conditions.
COMMENT
The couple was evidently taking measurements of a plot of land when caught by the avalanche. Both had skiis on and were holding the opposite ends of a measuring tape. It would appear that they were so occupied that they did not consider the danger from avalanches. TORBIT MINE, ALICE ARM, B.C. 7 APRIL 1959
One miner killed
WEATHER
Observations at Torbit Silver Mine, 300 m ASL
Temperature Precipitation O C
Date Max Min mm
3 April 6.5 0 2 3
4 April 6.5 1 .O 9
5 April 6.0 0 1.5
6 April 7.0 -1.5
7 April 8 .O -0.5
In March a total snowfall of 3.6 m accompanied by some rain was reported. On 7 April the temperature was above O°C and the snow was melting.
ACCIDENT SUMMARY
The surface railway at the Torbit Silver Mine extended for about 800 m along the side of a steep mountain between the mine and the mill. The entire length of track was covered by a snow shed.
On 7 April at about 1300 h the train crew made the second trip of the day from the mill to the mine. The switchman rode the first of five empty cars and the motorman the engine at the rear. When the train approached the mine an avalanche struck, broke the shed around the first two cars and buried the switchman in the debris.
RESCUE
After attempting, without success, to reverse the train the motorman and other helpers began to clear the debris around the lead car. After about twenty minutes the switchman was uncovered but showed no signs of life. Attempts to revive the victim were unsuccessful. AVALANCHE
The avalanche contained wet snow mixed with rock and appeared to be the result of high temperatures and snowmelt. It ran over a width of about 30 m and deposited debris to a maximum depth of 5 m in the snow shed. About 12 m of snow shed was destroyed.
COMMENT
A previous avalanche had occurred at the same site in March 1959 and another one eight years before that. The weight of the snowfall deposited on the shed appeared to have been a problem, and the removal of this snow was of greater concern to the mine management than avalanches. The snow was probably already so heavy that little additional weight from the avalanche was required to break the shed.
REFERENCE
British Columbia Department of Mines and Petroleum Resources; Annual Report 1959; Victoria, B.C. MT. GARIBALDI, SQUAMISH, B.C. 19 JULY 1961
One climber killed, one injured
WEATHER
Temperatures ranged from 12 to 2S0c at Squamish during the week prior to 19 July. Precipitation of 3 mm was recorded on 16 July.
ACCIDENT
Three climbers left Vancouver 18 July intending to spend three days climbing in the Mt. Garibaldi area. When they arrived in Garibaldi Park they were told by work crews that it had not been cold enough at night for the snow to consolidate properly. Because of this the group decided to climb in the early morning hours. At approximately 0500 h the party was caught in an avalanche about 250 m below the Saddle Peak of Mt. Garibaldi. Two were injured, one severely, and the third was unhurt.
RESCUE
About one hour after the accident the unhurt climber left to summon help. At about 1100 h on the Diamond Head road he met a Provincial Parks employee who drove him to the police station in Squamish. The Royal Canadian Mounted Police notified the Air Force Search and Rescue Group at Comox who in turn dispatched a helicopter for an aerial search.
At around 1600 h a second member of the party was noticed scrambling down the slopes below the accident site. He was picked up and flown to the Diamond Head Lodge. He was, however, unable to pinpoint the third person's location. The helicopter crew finally located the avalanche and the third member of the party but was unable to land there. A ground crew was organized and dropped about one hour's hike from the accident site. At 2240 h the rescue group, on foot, reached the victim who had died from severe chest injuries.
COMMENT
The climbers had essentially the right idea, to complete the climb early in the morning. Unfortunately they had not realized that the night temperature had not dropped low enough for the wet snow to stabilize, therefore that avalanche hazard can be high after a warm night. SILVER STAR SKI AREA, VERNON, B.C. 21 JANUARY 1962
One skier killed
WEATHER
Observations at Vernon BX climate station,'516 m ASL
Temperature Precipitation . Oc
Date Max Min mm
17 January -10 -15 Ni1
18 January - 15 -19.5 Ni1
19 January - 16 -19.5 , Trace
20 January -15 -25.5 Ni1
2 1 January -14 -25.5 Ni1 \, i
Between 13 and 16 January 13.7 mm of precipitation was recorded at Vernon BX station.
ACCIDENT
Shortly before noon on 21 January a local ski racer decided to set a downhill course on Silver Star mountain. Together with a younger companion he gathered a few slalom poles and started from the top of the pomalift. A short distance beyond the second gate the younger skier fell, and his harnesses released. The other skier continued to set the third gate while his companion remained behind to fix his skis. When the young skier was mobile again he skied to the third gate but found no sign of his friend, only the gate poles and a "break" in the snow nearby. Thinking nothing of the "break1' (fracture) he continued skiing down assuming that his friend had left.
Another skier resting at the chalet noticed an avalanche just before 1200 h but did not think that anyone might be trapped in it. At 1310 h he ascended part way up the pomalift then traversed the slope towards the avalanche looking uphill for further potential avalanches. When he skied to a point below the avalanche deposition he noticed a pair of skiis lying on the surface in the midst of the avalanche deposition about 60 m above him.
RESCUE
The person who discovered the skis on the avalanche realized that some one could be buried there. He skied to the bottom of the hill, alerted the ski patrol, then mounted the lift and returned to the site. He felt it would be faster to ride the lift than to climb the 60 m uphill for an inspection. A ski instructor, experienced in avalanche rescue and alerted by the ski patrol gathered volunteers and some long sticks for probing.
The first rescuer to arrive on the site discovered the victim's boots and one arm protruding from the snow. Digging by hand proved unsuccessful, only shovels could penetrate the hard, chunky snow to the victim's head approximately 75 cm below the surface. The rescuers attempted artificial respiration, but were unsuccessful in their attempts to revive the victim. A doctor ordered the rescuers to remove the victim by toboggan to the ski patrol shack where he was pronounced dead due to suffocation.
AVALANCHE
The avalanche, which fractured just below the third downhill gate, was triggered by the skier. The slab fracture occurred in wind crusted snow and varied in depth from 30 to 75 cm. The starting zone, which had a gradient varying from 30' to 3S0, held a SSE aspect with ground surface of mixed scrub vegetation and broken shale. The avalanche ran a distance of 220 m and was 15 m wide. It deposited snow to a maximum depth of 1.2 m. The deposition was described as being a combination of hardpacked snow and large angular chunks.
COMMENT
The victim was a local racer and a member of the volunteer ski patrol. He set the third gate in a flagged non-skiing area of the mountain, where the snowpack was probably rarely disturbed and therefore prone to deep instability. Avalanches are rare at the Silver Star Ski Area and it is not surprising that the victim's companion thought nothing of the "breaks" he saw in the snow near the gate.
After the accident some bulldozer work was done in the gully with the expectation of reducing the hazard, but avalanche conditions still develop on an infrequent basis. SKI TRACK OF VICTIM , 0 PREVAILING ROCKY I \
DEEPEST FRACTURE
ROAD
LARGE CHUNKS"\ \ IN DEPOSITION LOCATION OF BURIED BODY
Figure 3 Sketch of the accident site, Silver Star Ski Area OCEAN FALLS, B.C. 13 JANUARY 1965
Seven residents killed, five injured, several buildings destroyed
LOCAT I ON
The town of Ocean Falls is at sea level on the Pacific Coast about 500 km northwest of Vancouver, B.C. The climate is very wet with a mean annual precipitation of 4400 mm.
WEATHER
Observations at Ocean Falls Townsite 5 m ASL
Temperature Precipitation O C
Date Max Min mm
9 January 1 -5 10
10 January 1.5 - 3 16
11 January 1.5 0.5 34
12 January 3.5 0.5 21
13 January 5.5 1 133
Between 31 December and 8 January 136 cm of new snow was recorded at Ocean Falls. Extremely heavy rain fell at the townsite on 13 January.
ACCIDENT SUMMARY
The threat of flooding and slides became prevalent as heavy rainfall continued during the evening of 13 January. At 2030 h the western end of the ground floor at t"I'he Willowstt apartments was flooded by slush and water. The Royal Canadian Mounted Police assisted the tenants to evacuate the building. Because of the increasing avalanche hazard the Police also decided to close the road between the townsite and Martin Valley, a subdivision 1.5 km west of the town. At approximately 2130 h power and telephone communications were interrupted. At 2200 h an avalanche came down a gully from Mt. Caro Marion carrying trees, mud and boulders. At the lower end of the gully it separated into three arms, two of them followed watercourses on the alluvial fan. The arm in the westerly creek destroyed half a duplex house above Burma Road, knocked down the porch of a second duplex and finally demolished the end rooms on a bunkhouse at the water's edge. The easterly arm struck and completely destroyed another duplex above Burma Road, carried the wreckage downhill and struck the print shop and Credit Union buildings below. Both were destroyed and two adjacent buildings were partially damaged. The wooden roadbed of Burma Road was also torn out by the avalanches. Three of the seven persons residing in the western duplex were trapped in the undestroyed portion of the home. The other four persons and the three persons residing in the eastern duplex were engulfed by the avalanche. RESCUE
Police officers and volunteer rescuers were working at the Willows Apartments just east of the accident site when the destructive avalanche occurred. The rescuers immediately began a search of the avalanche debris, freed the three trapped persons, and recovered two bodies within one-half hour after the avalanche. The injured persons were evacuated to the town hospital where an emergency power system had been set up. The paper mill was shut down when news of the disaster was received, and the workers joined the rescue parties. The townspeople living around the avalanche area were advised to leave their homes and take refuge at the hotel or the mill. Those residents in areas cut off by the slide were evacuated to safe positions by boat. At 0200 h on 14 January another avalanche which ran down between the two earlier tongues occurred. Rescue efforts were called off until dawn. The ship Northland Prince arrived on its regular run at 0430 h and stayed in port until the damage and further potential danger could be assessed. At dawn the rescue effort was renewed. It was extremely slow going because of the mixed snow, mud, rock, and wrecked timbers. The long-distance telephone communication was reestablished at 0700 h. The search continued for several days until the last two bodies were recovered 19 January. In all seven persons were killed and five injured . AVALANCHE
Mt. Caro Marion rises to an elevation of 1234 m above the Ocean Falls townsite. The avalanche path in question starts at an elevation of approximately 915 m on the south slope of the mountain and runs over much of its vertical fall in a rock canyon approximately 25 m wide. The average gradient in the canyon is approximately 45'. The avalanche of 13 January started in the canyon between 400 and 500 m elevation. The canyon opens into an alluvial fan over a talus slope at approximately 120 m elevation.
The avalanche was the result of heavy snowfalls in early January followed by high temperatures and heavy rain on 13 January. Local residents mentioned a freezing rain in December which coated the town with ice. The ice layer, when lubricated by the rain, might have provided an initial sliding surface for the deep snow. The avalanche was probably triggered by wet snow sluffing from the canyon walls, and once in motion collecting additional wet snow, mud, boulders, and trees. Several other avalanches ran on Mount Caro Marion during the same night, but caused no damage other than blocking the road to Martin Valley in four places. COMMENTS The avalanche 13 January 1965 was an unusual occurrence caused by a combination of adverse weather factors. Such avalanches might only be observed once in 50 to 100 years. The older residents of Ocean Falls could not remember avalanches reaching the townsite before. The only large avalanches in memory were two of mixed snow and mud that crossed the Martin Valley road 2 December 1957. That day 216 mm of rainfall was recorded.
This case illustrates the need for zoning studies before a subdivision is built. The avalanche tracks above the residential areas can easily be recognized, and from studies of the terrain, the tree growth, past avalanche activity, and calculations of the theoretical runout distance the extent of any possible large avalanche could have been determined. Either no buildings should have been placed in the dangerous zone or defences should have been provided for their protection. After the accident small dikes were bulldozed along the track of the destructive avalanche, but they were no longer evident in 1978. Figure 4 Mount Caro Marion and townsite with the avalanche track in the centre -22- ROCK CANYONY\ MATURE TIMBER; SLOPE INCLINE 30" MATURE TIMBER; SLOPE INCLINE 30"
COUS I NS I NLET
Figure 5 Sketch map of the accident site showing the extent of the avalanches MT. ST. ELIAS, YUKON TERRITORY 11 AUGUST 1971
Four climbers killed
On 11 August, after completing ascents on Mt. Logan, five members of an expedition party attempted an ascent of Mt. St. Elias from the Newton Glacier via Russel Col, the original route climbed by the Duke of Abruzzi at the turn of the century.
WEATHER During the afternoon o$ 11 August the temperature was above 0°C and it was sunny although the NE face of St. Elias was in the shade. The climbers had observed extensive avalanche activity on the south-facing slopes of Mts. Newton and Jeannette but not on St. Elias or Russel Col. There was, however, evidence of old avalanche tracks and depositions on these slopes.
ACCIDENT At approximately 1600 h the climbers, travelling on two ropes, were about 90 m above the Newton Glacier on the 750 m high slope leading to Russel Col. Hearing a loud crack the climbers looked up and saw an avalanche coming off the NE face of Mt. St. Elias and spreading across the slope above them. The group attempted to dig in, but the entire party was swept away within 5 or 6 seconds. When the avalanche had stopped only one climber (who was on the lead rope) and a stuffsack remained on the surface. RESCUE
After unsuccessfully attempting to pull up the buried rope and to dig with his hands, the survivor, in a state of shock, headed back down the route without pack, snowshoes, or ice axe. He collected some food from the party's cache on the Newton Glacier, as well as from the caches of other expeditions, and headed for the main cache on the Seward Glacier. After spending the night on Newton Glacier he arrived at the Seward Glacier cache late on 12 August and radioed the Arctic Institute of North America station at Kluane Lake. The following day he was picked up by helicopter and flown to Kluane Lake. The bodies of the other climbers were not retrieved because of their remote location and the hazardous conditions. AVALANCHE DATA
The avalanche was initiated by glacial ice blocks breaking off the steep slopes to the south of Russel Col at approximately the 3400 m level. As large amounts of wet snow were picked up during the motion of the avalanche, it consisted of mixed wet snow and ice blocks. The deposition, which settled and hardened very quickly, was 60 m wide, 20 m long, and 2 to 3 m deep.
COMMENT
The survivor felt that the party should have recognized the avalanche danger in view of the old deposits and current activity, but the absence of any avalanches running near the climbing route on that particular day made the climbers feel confident.
REFERENCE
American Alpine Club and Alpine Club of Canada; Accidents in North American Mountaineering, 1971.
( HALL PARTY ) Y- ,
Figure 6 Map of scale 1:250,000 NINE MILE MTN., near HAZELTON, B.C.
One snowmobile operator killed
WEATHER
Observations at New Hazelton climate station. 313 m ASL
Temperature Precipitation " C
Date Max Min mm
10 March 5.5 0.5 3.0
11 March 7.0 0 Trace
12 March 6.0 -0.5
13 March 6.0 -5.5
14 March 8.5 -1.0
Several days of freeze-thaw had been experienced at Nine Mile Mountain. On 14 March the snow surface was firm in the drea.
ACCIDENT SUMMARY
A party on six snowmobiles left Hazelton 14 March to spend the day at a cabin on Nine Mile Mtn., approximately 10 km northeast of Hazelton. The group travelled parallel to Two Mile Creek then ascended by road to the cabin at the 1475 m level. In the afternoon they decided to sortie north along the west facing slope at Nine Mile Mountain .
Two snowmobiles were leading a climbing traverse below the ridge, one slightly ahead and above the other. Suddenly the second driver noticed snow washing up against his machine and looking ahead saw that the other vehicle was also being washed by avalanching snow. The lead driver was running along on the uphill side of his machine, presumably trying to prevent it from rolling over. Realizing what was happening the second driver opened his throttle and turned downhill with the avalanche. After momentarily losing consciousness he found himself sitting with his machine a few metres from the edge of the avalanche deposition. There was no evidence of the lead machine. The time was approximately 1600 h.
RESCUE
The second driver immediately proceeded to a spot in the avalanche deposit about 25 m away, near the base of some small trees, and began to dig. A few moments later the other four drivers, who had been waiting in the saddle near the cabin, arrived. Asked why he was digging in that particular spot the second driver could only answer that he knew the victim was there. One machine returned to the cabin for shovels and first aid equipment. I Just as that machine returned the second driver located the ski of his companion's machine about 1.5 m below the surface. The group continued digging with shovels and found the victim face up, blue and not breathing, underneath the overturned snowmobile 2.2 to 3 m below the snow surface. Approximately 40 minutes had elapsed since the accident occurred. Removing the victim from the hole was very difficult because the snow had set like cement. A trained first aid man in the group attempted cardio-pulmonary resucitation but to no avail. The body was taken to Hazelton on a first aid toboggan that had been stored at the cabin.
AVALANCHE
I The large dry snow avalanche containing both a slab and a broken cornice was probably triggered by the passage of the snowmobiles. The fracture line had a maximum depth of 4 m, and the avalanche ran on or near the ground. Wind during the winter had scoured the ridge and deposited the snow on the avalanche slope. The majority of the avalanche snow, both chunky and fine in texture, was deposited at the slope transition. I COMMENT The slope in question was fairly short and was described by the survivors as not being particularly steep. It was steep enough, however, to sustain some cornice development along the ridge, a sure sign of potential avalanche hazard. The group found the snow surface firm enough to allow walking, but perhaps a snowpit observation would have revealed deep instability.
Eye witness observations about the victim's last seen point, and any surface clues are critical in locating rapidly buried persons. In the present case the second driver must have subconsciously recorded the location where the first driver disappeared which led him immediately to the correct spot. N- ALMOST NO DEFINED FRACTURE
FRACTURE APPROX 4 m AND CORNICE BREAK
APPROX 300 m
+ LAST SEEN POINT OF THE VICTIM @ LOCATION OF THE BURIED VICTIM X LOCATION OF THE SECOND DRIVER WHEN THE AVALANCHE STARTED @ LOCATION OF THE SECOND DRIVER AFTER THE AVALANCHE --- PATH OF THE SNOWMOBILE
Figure 7 Sketch of the accident site Nine Mile Mountain WESTCASTLE SKI AREA, ALBERTA 13 FEBRUARY 1975
One machine damaged, operator injured
WEATHER
Observations taken at Westcastle Day Lodge, 1415 m ASL
Temperature Precipitation Snow Foot Wind "C Depth Penetration (est .) New Storm Snow Snow Date Time Max Min cm cm cm cm
9 February p.m. 14
10 February 0630 0 -15 13 no obs. 113 55 light S 1830 -4 -19 12 33 119 5 8 light - m0d.N
11 February 0640 -19 -22 6 37 122 62 mod.NW 1945 -20.5 -22 22 5 7 138 78 light N
12 February 0630 -21 - 2 2 16 no obs. 152 78 calm 1945 -18.5 -22.5 39 93 175 120 light - mod.SW
13 February 0630 0 - 16 6 86 164 no obs. light - mod.NW 1825 1 -14 9 85 162 107 mod. NW
At approximately 2000 h on 12 February a warm air mass, which had earlier enveloped the upper mountain, sank to the Day Lodge at the base of the ski area causing the temperature to rise 13.S°Cin a few minutes. On 12 and 13 February observers at the top lift station reported moderate and gusting winds from the southwest.
A snowprofile taken 9 February at the top of Shotgun Gulch (1800 m elevation, ENE aspect) revealed 50 cm of temperature-gradient snow near the ground, overlain by 1 m of equitemperature snow and partially settled new snow at the snow surface. AVALANCHE OBSERVATIONS 10 February Explosive control produced numerous avalanches and extensive settlement. 11 February Controlled avalanches on N, NE, and E exposed slopes (including Shotgun Gulch).
12 February Controlled small avalanches on N, E slopes; one 25 cm deep fracture on NE exposure.
ACCIDENT SUMMARY In mid-February 1975 the Canada Winter Games were held at Westcastle Ski Area. A storm began 9 February and by 12 February a large amount of new snow had accumulated. The visibility at the avalauncher gun at the top of the T-bar lift station was limited to 200 m. Due to the poor visibility and an expectedly high number of unexploded projectiles, the avalauncher gunner did not want to fire blindly. Control by hand charges along an alpine route was attempted but was abandoned because of the avalanche hazard and poor visibility. On the morning of 13 February the visibility had improved although Chinook conditions prevailed in the alpine region. At 0730 h the avalanche control team noted an abrupt temperature increase while ascending the T-bar lift. The first avalauncher shot was fired into the south side of the North Cirque and released a large avalanche which ran down Shotgun Gulch to the Bunny Hill (Figure 8). A second shot was fired into the north side of the North Cirque resulting in a second, larger avalanche that destroyed the old upper lift base then moved down Shotgun Gulch, crossed the Bunny Hill, and struck a grader on the road below. The force of that avalanche blew out the windows of the grader and snow pinned the operator against his seat. RESCUE
Only about 50 cm of snow was deposited around the grader wheels so rescue workers were able to free the operator from the cab then drive the grader clear of the avalanche path. The grader operator was taken to the hospital with minor injuries. A helicopter parked on a temporary pad just below the road was not affected by the avalanche. AVALANCHE DATA Both avalanches of 13 February ran on a lubricating layer of 15 cm of light dry snow which was deposited at the beginning of the storm. , The second avalanche started at an elevation of approximately 2050 m and ran out at an elevation of approximately 1400 m. The first fracture occurred on a slope with an ENE aspect and the second on an ESE slope. COMMENT
It should not happen that a vehicle be in the path of avalanches that are released by gunfire. This accident occurred because of lack of communication between the avalanche control team and the grader operator. Strict control of traffic, including private vehicles, maintenance equipment, and skiers is an essential part of avalanche control by explosives. The measures include radio contact between the control personnel, road blocks, and maintenance vehicles.
The avalanche control team at the Westcastle Ski Area did not expect the second avalanche to be as large as it was. In theory the first avalanche, starting at a leeward slope and picking up unstable snow in the track, should have had a greater volume than the second, but the snowfall, together with high temperatures and a moderate wind of variable direction appeared to have deposited deep, rather cohesive snow at the Northside of the Cirque, and this snow fractured over a wide area.
One of the objectives of control by gunfire is to release small avalanches through repeated firings during snow storms and thus prevent the formation of large, destructive avalanches. Unfortunately the old model avalauncher was unreliable for blind firing and the snow could not be released continuously in small amounts. SECOND AVALANCHE Fl RST AVALANCHE
-N
SHOTGUN GULCH
ROAD
Figure 8 Sketch of the avalanche path Figure 9 Map 1:50,000 with fracture of the avalanches MT. FISHER, near CRANBROOK, B.C. 11 JUNE 1976
Three mountain climbers injured
WEATHER
The sky was clear and the temperature average during the week prior to 11 June. The forecast predicted the same weather would continue, however between 1130 and 1200 h on 11 June a warm air mass struck the area.
ACCIDENT SUMMARY
Three climbers left a logging road on Boulder Creek at 0630 h for a climb on the North Face of Mt. Fisher, 2838 m elevation, over a mixed snow, ice and rock route. Between 1130 and 1200 h while cramponing in a snow couloir some 180 m below the peak, the group noticed a change in the weather. The temperature began to rise, mists began to roll over the peak, and the snow began to soften. About one-half hour later the climbers reached the top of the couloir where they removed their crampons in anticipation of assaulting the final 60 m of rock.
After some discussion the climbers decided that in view of the increasing avalanche hazard they should descend rather than continue. Descending through the couloir the group reached an open snow slope and stopped to discuss their next move. The options were either to wait for a freeze-up or to cross the snow slope. Choosing the latter they traversed the snow slope with two ropes joined, belaying from a safe position. The ropes were not quite long enough for the lead climber to reach a safe spot before the middle climber had to advance even though the lead climber was still moving. The lead climber had just reached the far side of the snow field and was in the process of putting in a firm belay, when the middle man, a full rope length behind, was hit by a small, fast avalanche and carried downslope. The lead climber's belay held the middleman, but the third climber was pulled out of his ice axe belay and fell onto rock and snow below. The rope between the lead and the middle climber then broke and the middle and third climbers continued their fall. When they came to rest the two men were still roped together, were suffering from various injuries, and their helmets were badly damaged.
RESCUE
After regaining their wits the two climbers decided to part. One would climb with all the spare clothing to the person above, who had called down saying she was hurt, while the other would go for help. The time was about 1400 h. The descending climber reached a house at 1800 h and telephoned the Royal Canadian Mounted Police requesting a helicopter. The helicopter arrived shortly after 2000 h, picked up the climber and flew with him over the accident site where the two remaining climbers could be seen digging a snow cave. The helicopter then picked up three friends in the valley who had overnight equipment and dropped them at the base of the mountain just as darkness fell, about 2230 h. They reached the accident site at about 0100 h, just before rain began to fall.
At first light on 12 June a heli-rescue team arrived from Banff, and at 0600 h the rescuers, slung below the helicopter, brought out the injured victims and the rescue party. By 0800 h the rescuers were evacuated to Fort Steele and the victims to Cranbrook Hospital.
AVALANCHE
The two climbers fell a total distance of about 450 m from an elevation of approximately 2400 m. The small wet avalanche caught the climbers on a north facing slope inclined at about SO0.
COMMENT
If the climbers had turned back as soon as the weather began to change they might have escaped the accident. After the accident they realized that they had ignored a third option to avoid the unstable snowfield, i.e., to descend directly from the couloir to an ice cliff that they had ascended earlier and rappel from it to safer slopes below. Being caught by the avalanche was bad luck but to survive the 450 m fall was fortunate indeed. The climbers felt that without helmets they would not have had a chance for survival. SUNSHINE VILLAGE, BANFF NATIONAL PARK, ALBERTA 11 DECEMBER 1976
One skier buried
WEATHER
Observations at Sunshine studv lot 2145 m ASL
Temperature New Precipitation Snow Wind OC Snow Depth
Date Time Max Min cm mm cm km/h
7 December 0800 -6 -10 4 2 45 S 23 1500 -4 - 7 1 1 46 SE 23 8 December 0800 -2 -5 5 6.5 48 S 32 1500 -2 -3 Trace Trace 48 S 29
9 December 0800 -2 -19 19 12 64 S 16 1500 -9 -11 1 Trace 65 S 7
10 December 0800 -9 -16 1 1 58 S 30 1500 -6 -10 3 2 57 SE 27 11 December 0800 -5 - 7 7 7 62 S 32 1500 -4 - 6 7 3 69 S 10
Strong southerly winds were recorded at the Sunshine study plot between 1000 h 10 December and 1000 h 11 December. December 11th was the first day of operation of the ski area and only a limited number of runs were open to the public. Virtually no consolidation had taken place in the snowpack at this time.
ACCIDENT SUMMARY
Three skiers attempted to ski the closed "Bunker's Run" from the top of the Standish Chair Lift. After being informed by the lift operator that the area was closed, they skied in the direction of Jerry's Run, but a short distance down the hill they ducked under the rope fence, passed a "No Skiing" sign, and entered Bunker's Run. The group then proceeded to the Donkey's Tail, and in doing so passed several boundary poles and a sign that read "Danger, Avalanche Area, Closed". Enroute they triggered a small avalanche in the Standish Face area.
At the Donkey's Tail the group started to ski down. The first skier safely reached the bottom of the slope but the second skier fell about mid-slope. As the third skier entered the top of the slope an avalanche released that carried the fallen skier down and buried him at the transition of the slope. The first and third skiers escaped burial. The time was 1000 h.
RESCUE
A group of ski instructors who had witnessed the accident went to the site immediately. The avalanche and the reaction of the ski instructors were observed from the ski lift and reported to the Parks wardens who left the bottom of the lift by snowmobile with equipment for a hasty search at 1010 h. Meanwhile the ski instructors had made a surface search, marked the last-seen point, and formed a probeline at the bottom of the deposition using upturned ski poles.
At approximately 1007 h one of the survivors located the buried skier who was blue in the face and not breathing. A rescuer began to administer artificial respiration and the victim responded immediately. At 1015 h the park wardens and the ski patrol arrived, placed the victim on a fracture board, and removed him with a toboggan to a waiting ambulance.
AVALANCHE DATA
The avalanche, triggered by the skiers, ran on the ground in an unstable base of depth hoar. The slab fractured with a depth of 70 cm, and a width of about 15 m, and ran about 45 m vertically. The slope had a NE aspect, was in the lee of the prevailing wind, and was inclined approximately 40° in the starting zone.
COMMENT
Signs reading "High Avalanche Danger" and "Only Jerry's Run Open" were placed at the bottom of Standish Chair Lift. The group of skiers consciously violated the closures and came very close to a tragedy.
The ski instructors had recently practiced avalanche rescue techniques and knew how to initiate an organized search immediately. This emphasizes the value of teaching avalanche awareness and rescue techniques to ski area staff and instructors who work in areas with avalanche problems. E w E 0- E UY U * U TEMPERATURE, "C w- C y -> Z c- a 5: I I -I I I I z * N Lu m 3 U> I InZ we -12 -10 -8 -6 -4 -2 -WE, z oI Q a - z LE 2IE E ma U a CI
X AIR TEMP. - 60
- - 50
- X 40 I +I\ 1 - I 0 4, - 30 1 TO 2 0.14 - \ - \x, \ 20 < - '. - 10 A 4+ 0.18 , X.. . '. . -
Figure 10 Snow profile of 6 December at Sunshine Village study plot 2145 m ASL Figure 11 View of the avalanche site (Photograph courtesy Parks Canada) Key : + Victims last seen point @ Location of buried victim x Third member of the party CHANCELLOR PEAK, YOHO NATIONAL PARK, B.C. 12 DECEMBER 1976
Three mountain climbers killed
WEATHER
Observations at Westgate Yoho National Park 1065 m ASL
Temperature New Snow
O C Snow Depth Date Max Min cm cm
8 December, AM 1 PM 3
9 December, AM PM
10 December, AM - 4 - 12 12 PM - 1 - 6 T
11 December, AM + 1 PM + 2 12 December, AM - 2 -13 PM - 2 -12
On 12 December the wind was calm and the sky cloudy.
ACCIDENT SUMMARY
On the morning of 12 December three climbers registered with the Parks authorities intending to climb the NW ridge of Chancellor Peak and return the next day. The trip was considered a training climb for the two youngest members of the team. Departing from Hoodoo Creek campground (12 miles west of Field on Highway 1) the group climbed to the 2500 m level. Tracks indicated that the climbers descended from this point into a gullied, avalanche prone area on the west face, where they appeared to have done some practice climbing. When they returned to the ridge they were caught in an avalanche at the 2400 m level, carried over steep rocky terrain and buried at the 1850 m level. RESCUE
A morning check of the registration book 13 December indicated that the party was due at 1100 h. Between 1100 and 1200 h the parks staff received a call from a concerned family member stating that the climbers had not yet returned.
After a check at Hoodoo Creek campground revealed no sign of the group's return the park wardens initiated a ground search at 1300 h. At 1335 h a helicopter was called for from Banff together with a tracking dog and dog master. An aerial search along the foot tracks of the missing party led to the discovery of a recent avalanche and of objects on the surface of the deposit. At 1545 h park wardens landing on the site with the aid of a sling beneath the helicopter found clothing and a packsack on the deposit. At 1550 h the first victim was located under 0.4 m of snow. The rescuers followed the climbing rope attached to the body and at 1615 h found the second victim 0.6 m below the snow surface and the third one buried 1.2 m deep. All were dead when discovered. By 1645 the bodies and the rescue party had been evacuated to Hoodoo Creek by helicopter. One victim was later determined to have died of a broken neck while the others died of suffocation.
AVALANCHE
The avalanche was a dry slab probably triggered by the victims, that ran on the ground and was chanelled in a gully. The gully was approxi- mately 10 m wide and had an average gradient of 45" over its 550 m vertical fall. The maximum depth of the deposited snow was 1.5 m. The snowpack in the area was estimated to be 40 cm deep and was comprised mainly of depth hoar.
COMMENT
The avalanche had a small volume, but ran on rock and scree. Owing to injuries sustained during the fall the climbers probably were unable to fight to stay on the surface.
The snowfall in November and December of 1976 was unusually light and the shallow snow cover turned into depth hoar in almost all mountain areas of southern British Columbia. Drifting snow formed a hard layer over the weak temperature-gradient snow in gullies and the climbers ' probably felt the small amount of snow in the gully with such a hard surface would be safe. It could be that they believed the conditions " were similar to those on a cold day in the summer when the gullies are usually filled with dense, stable snow. Figure 12 Avalanche deposit with the rescuers digging for the victims. (Photo courtesy Royal Canadian Mounted Police) 28 DECEMBER 1976
One snowmobile operator killed, one injured
LOCATION AND WEATHER
The accident site is on the shore of the St. Lawrence River, 3 miles east of Tadoussac, Comt6 Dubuc, Qu6bec. December 28th was a clear, calm day.
ACCIDENT I A party on three snowmobiles triavelled through a snow covered sand dune area. While they were traversihg the bottom of a steep slope an avalanche released from above and stiruck them. One driver was completely buried, a second was injured and the third one escaped. Two of the snowmobiles were destroyed. The time of the accident was approximately 1400 h. RESCUE
An intense search for the buried victim was initiated at 1600 h and continued until 2100 h when the victim's body was located underneath 4 m of snow. AVALANCHE The slab avalanche, probably triggered by the snowmobiles, occurred on a south facing slope, was 250 m long and 300 m wide, and deposited snow to a depth of from 3 to 4 m. Northwest wind had accumulated deep packed snow on a base of what was described as granular snow. COMMENT The granular, loose snow at the avalanche bed surface was probably the result of a temperature gradient. As other cases have already demonstrated the possibility of avalanches in eastern Canada must not be ruled out. PARKER RIDGE, BANFF NATIONAL PARK, ALBERTA 15 FEBRUARY 1977
One skier killed
WEATHER
Observations at Parker Ridge study plot 2030 m ASL
Temperature New Snow Average OC Snow Depth Wind
Date Max Min cm cm km/h
11 February 4 -10.5 2 74 SW 27
12 February -0.5 -10.5 2 76 SW 32
13 February 1.5 -10 7 79 SW 35
14 February 3 -15 74 SW 18
15 February 1.5 -11 73 SW 35
February 15th was a cool, cloudy day at Parker Ridge.
ACCIDENT SUMMARY
On 15 February seven people who were staying at the Hilda Creek Youth Hostel skied in the Parker Ridge area. At approximately 1600 h four of them came to a short steep slope close to the Hostel. The leader, watched by another member of the group, entered the slope from the side just below a small cornice and fell. The observer had turned his head toward the other skiers but his attention was attracted by a sound coming from the slope in front. When he turned around he discovered that the slope had avalanched and the group leader had disappeared.
RESCUE
The skiers began a search of the deposition while one of them went to the Hostel for help. The driver of a passing car was notified and in turn contacted the Jasper Park Wardens by phone from the Tangle Creek work camp at 1635 h. A party of three wardens and a trained avalanche dog were dispatched from Jasper at 1655 h. Meanwhile the ski party members had begun digging where they thought the victim was buried, which later proved to be 10 m away from the actual location. At 1745 h the park wardens' first search party arrived. By this time the survivors had dug up a large area of the avalanche deposition. At 1750 h the dog located the victim buried under about 60 cm of snow. He was dug out and cardiopulmonary resuscitation attempted but the victim had died of suffocation.
AVALANCHE
Prevailing southwesterly winds had loaded the top of the slope and at the same time scoured the bottom leaving a very unstable "hanging" slab. This was evident by the absence of a "stauchwall". The avalanche was a hard slab with a depth varying between 2 and 70 cm, and moved only a short distance. The shear failure occurred on a crust, which was covered by surface hoar, approximately 20 cm above the ground (Figure 13). The slope had an ENE aspect and an incline in the starting zone of 35 to 40°.
Another fatal avalanche occurred at the same location 9 December 1967. (Stethem and Schaerer 1979)
COMMENT
The party was inexperienced in ski mountaineering and had neither registered nor discussed avalanche conditions with the National Park Wardens.
The survivors made a serious mistake by digging immediately in the avalanche snow where they thought the victim was buried. When they did not find him there they continued digging nearby. By probing first with skipoles and skis they would have been much more successful in locating the buried person. It was unfortunate that the others were not watching when the skier was caught in the avalanche
REFERENCE
Stethem, C.J. and Schaerer, P.A. Avalanche Accidents in Canada. I. A Selection of Case Histories, 1955 to 1976. National Research Council of Canada, Division of Building Research, NRCC 17292, P. 39-40. Figure 13 Fracture line profile, observed on 16 February 1977 by Parks Canada
m l VVI IIYC>> - BROKEN-- SLAB --
BURIED VICTIM
Figure 14 Sketch of the accident site
- 45 -
DIANA LAKE, ROCKY MOUNTAINS, B.C. 16 MARCH 1977
One skier killed
WEATHER
Snowfall prevailed on the morning of 16 March at Diana Lake, depositing about 10 cm of new snow.
ACCIDENT
Ten skiers plus a guide waited in a cabin near the lake planning to helicopter to a ski run when the weather cleared. At 1230 h weather had improved and the guide decided to take the party out after lunch.
For the first run the guide chose a gully on Table Mountain Ridge, adjacent to the lake. The helicopter dropped the group on the ridge top, elevation approximately 2450 my and from there the skiers traversed towards the gully. The guide skied to a rock outcrop part way down the gully where he waited for the rest of the group. Then he continued his descent, stopped at another outcropping, about two-thirds of the way to the bottom, and after gathering his clients, directed them to continue in the gully to the helicopter pick-up while he would follow at the rear. When the first couple of skiers reached the trees in the meadow below the gully, an avalanche released from a slope above and adjacent to the gully. Although the guide and other party members shouted warnings, some skiers who were near the transition of the gully to a broader slope below, were caught. The time was approximately 1515 h. RESCUE
One buried person was discovered immediately after the avalanche came to rest. A head count revealed that a second must be buried and a transceiver search was initiated. All members of the party were wearing, and had practiced the use of, avalanche rescue transceivers. About 20 minutes after the accident the second person was located by transceivers and probing. He was buried about 1.2 m below the snow surface at the base of a small tree and, as was concluded later, had died almost instantly from the impact of hitting the tree. A doctor and a police officer were later flown to the site, and the victim's body removed to Golden.
AVALANCHE
The avalanche started as a slab that fractured to a depth of approximately 30 cm in old snow layers. It ran over 200 m difference of elevation with a width of 45 m and deposited snow to a maximum depth of 2 m. The gully itself had a SSW aspect, but the avalanche started on a WNW slope at an elevation of 2400 m. COMMENT
Only 1.5 m of snow had accumulated at Diana Lake until 16 March whereas the normal accumulation would be 4 to 6 m. Owing to depth hoar and surface hoar formed in December and January the snow cover was in a critical condition throughout the Rocky Mountains in March 1977. Previous to the accident the guide of the party had released numerous avalanches by ski cutting in order to stabilize the ski runs, and the usual response of the snowpack was an abrupt settling and deep slab fracture.
The fatal avalanche fractured approximately 250 m from the nearest point of the route that the group followed. An alpine ski touring party had made about four runs on the same exposure on the previous day without noting any avalanche activity, but probably the snowfall in the morning and the sun in the afternoon of 16 March decreased the stability of the snow to a critical level. Although the skiing party found the snow stable in the gully, shocks created by skiing and transmitted through the snowpack could have produ'ced the failure on an adjacent slope. It was also speculated that the propwash of the helicopter flying across the avalanche starting zone after he dropped off the skiers and when it landed at the bottom could have disturbed the already delicate balance of stresses and strength in the snowpack. In any case the snow was already in a very unstable condition and the skiers just as well as other small disturbances could have triggered the avalanche.
Steep gullies are best avoided whenever there is even a remote chance of an avalanche, because they are collectors for drifting snow and avalanches that start on adjacent slopes. People caught in the channelled avalanche snow are often buried deep. BUGABOO, PURCELL MOUNTAINS, BRITISH COLUMBIA 17 MARCH 1977
Three skiers killed
WEATHER
Observations at Bueaboo Lodee. 1490 m ASL
Temperature Precipitation Oc
Date Max Min mm
13 March 0 -11
14 March -3.5 -18.5
15 March - 3 -22
16 March 0.5 -10.5
17 March -0.5 -16.5
The sky was partly cloudy on 17 March and the temperature approximately -6'~on the "Groovy Run" at 1500 h.
Natural avalanches had been observed on south slopes during the week prior to 17 March and the ski guides in the area were cautious.
ACCIDENT SUMMARY
Eleven persons and a guide were skiing in the area surrounding the Bugaboo Lodge 17 March. Shortly after lunch the group landed by helicopter at the top of "Groovy Run" where another group had preceded them. The guide traversed the slope beyond the tracks of the previous group and checked the snow by probing with the ski pole. Then he skied down the slope and signalled the group to follow.
The majority of the skiers reached the bottom safely, but as the last few moved onto the slope to descend, an avalanche released. Three out of the four skiers still at the top were caught and carried downhill. When the avalanche came to rest the three were partially buried but otherwise seemed all right. The rest of the group was clear of the avalanche and started to go uphill to help. A few seconds later a second, larger avalanche came down the slope and enveloped the partly buried victims. A warning shout from the guide allowed the others to move clear of the second avalanche. When the snow ha4 settled the three skiers who had been caught before were now completely buried. The time was approximately 1500 h.
RESCUE
The guide and other party members immediately wept to the area where the three skiers had been buried. The second avalanche had deposited a much larger volume of snow on top of the first. All the skiers carried rescue transceivers and the searchers picked up signals almost immediately when they switched their instruqents to the receive mode. After pinpointing the locations they began to dig. Other groups had been summoned by radio and additional help began to arrive by helicopter after about ten minutes.
The victims were buried between 3 and 5 m deep and digging became very difficult. The first victim was not found until 45 minutes had elapsed, the last one after 14 hours; all three were dead when found.
AVALANCHE
The avalanche started at an altitude of 2600 m and ran 150 m vertically over a width of 70 m. The initial fracture occurred near the skiers then propagated around a rock spur and across the top of the adjacent slope. The avalanche fractured in a layer of surface hoar 1.1 m below the surface, then tore into depth hoar and to the ground in some parts of the track. The avalanche slope had an average gradient of 39O and a NW aspect.
The area had been skied earlier in the week, but new snow had almost completely covered the old tracks.
COMMENT
The deep burial greatly reduced the chance for survival of the skiers who undoubtedly died soon of suffocation in the densely packed, deep snow. In spite of the rapid discovery of the burial spots by rescue transceivers and the large number of rescuers and shovels on site, it took too much time to dig into the deep avalanche snow. It is interesting to note that the victims were so deeply buried that the searchers could not pick up a signal with the lowest volume setting of the transceiver.
The case demonstrates again the hazard from a second avalanche from an adjacent slope after the first one has occurred. Figure 16 Photograph of the avalanche. The skiing party entered the slope from the left; the first avalanche broke at the left side, and the second, larger one came from the right. (Photo courtesy Canadian Mountain Holidays) @ Location of the buried persons BOW PEAK, BANFF NATIONAL PARK, ALBERTA 19 MARCH 1977
One climber killed
WEATHER
During the seven-day period prior to 19 March only 2 cm of new snow was recorded at the observation station at Bow Summit 2020 m above sea level. The temperatures for the period remained well below O°C. On 19 March the sky was overcast, the wind was light from the southeast, and the temperature reached a maximum of -5°C.
ACCIDENT SUMMARY
At approximately 1415 h on 19 March two climbers left their camp on Crowfoot Pass for a climb of Bow Peak via the north ridge. They had discussed the route with Parks1 staff on the previous day and had been warned to stay away from avalanche gullies. At 1730 h the pair had reached the summit.
The c limbers decided that they would glissade down a gully on the west face rather than to descend by the north ridge. When the first climber wa s approximately 200 m below the summit, the second one began his descent. As soon as he started glissading an avalanche released about 5 m above him. He was able to arrest himself with his ice axe and shouted "avalanche!" to his companion below. The first climber, however, was overrun by the avalanche and disappeared from sight.
RESCUE
Fearing further avalanches the second climber stayed put for a few minutes, then kicked steps down to the avalanche deposition and began to search for his companion. First he discovered a hat and then spotted a hand protruding from the snow about 3 m away. About 40 minutes had elapsed since the avalanche occurred. The survivor immediately dug out his companionls upper body and found him injured but breathing. The victim was unable to move as his lower body was still buried. After a half an hour of digging the second climber became exhausted but still had not freed the victim's legs.
The uninjured climber then decided to go for help because he thought it would take only half an hour to reach the Banff-Jasper Highway. He left his down jacket with the victim and made his way back to camp. After changing into dry clothing he headed down the trail, but failed to take a hat, gloves, jacket or snowshoes. The time was approximately 1900 h and the highway was about 8 km away. Shortly after leaving the camp the climber began to break through the crust and flounder in the snow. In darkness he crossed the Bow River, fell through the snow and ice, and on the other side began to follow a snowmobile track. Soon he became disoriented and realized that he could not go on. He made a bed of tree boughs and laid down for the night.
At dawn he walked to Bow Lake and after about 15 minutes reached the highway where he flagged down a passing maintenance truck. The driver immediately contacted the Park wardens by radio. Two wardens left Lake Louise by helicopter at 0750 h and landed at the accident site at 0820. The victim was found dead and was flown to a waiting ambulance on the Banff-Jasper Highway. Exposure was later determined as the cause of death.
AVALANCHE
The slab avalanche, triggered by the glissading climbers, had a fracture about 25 m wide and 1.5 to 2 m deep. The starting zone was at an altitude of 2800 m and the avalanche path was approximately 300 m long and 80 m wide with an average gradient of approximately 357. The avalanche snow was deposited to a maximum depth of 4.5 m.
COMMENT
The climbers were well equipped but had limited winter mountaineer- ing experience. They had been warned about the avalanche hazard by the Park wardens. As in other accidents, choosing a route through a snowfilled gully in the winter proved to be a fatal error. Panic perhaps clouded the judgement of the survivor. Had he rested a moment and thought the situation out he might have decided to free the buried man from the snow and set up an emergency shelter, thus saving the life of his companion. Figure 17 Westface of Bow Peak with the descent route of the climbers and the avalanche. (Photo Courtesy Jim Davies on 20 March 1977) Figure 18 Snow profile at Bow Summit observation plot 2020 m ASL on 21 March 1977. (Observed by Parks Canada) APEX MOUNTAIN, PENTICTON, B.C. 21 MARCH 1977
One skier killed, one skier injured
WEATHER
Observations at the base of Apex Ski Area at 0800 h
Temperature New Snow Date OC cm
18 March -6 2
19 March - 8 8
20 March - 2 2
21 March - 1 15
The snowfall ended at 0600 h 21 March, and at 1200 h the temperature was estimated at +3OC.
ACCIDENT SUMMARY
Five skiers, after skiing for a few hours in the new powder snow at Apex Mountain, left the pomalift at about 1300 h intending to ski the Tooth Chute, one of several chutes about 1 km away. No other skiers had yet entered the chutes on that day.
When they reached the chute three of the skiers prepared to enter it from the side about 10 m from the top. One of them began the descent, fell, and lost his ski, but was not observed by the others because he was below the apex of the hill. A second skier skied part way down, saw his fallen companion and pulled off to the side to wait. The third skier was about to go when one of the two waiting above jumped over a small cornice and began to turn. As he made his first turn an avalanche started and swept him down. The skiers at the side of the slope escaped, but the one who had lost his ski was enveloped by the avalanche. RESCUE
The skiers unaffected by the avalanche descended to the deposition area and one left immediately to summon help from the ski area. The skier who had been waiting beside his fallen companion indicated the last-seen point and the search began below that point. About ten minutes later the survivors heard one victim (the fourth skier) calling from the dense forest. They told him to wait and continued looking for the still missing skier. About 20 m below the last-seen point they found a ski pole and another 15 m below a hat. About 6 m further down the slope dense tree growth began where most of the snow seemed to have stopped. Helpers from the ski area began to arrive and initiated a hasty search with probes below the last-seen point concentrating it towards the dense trees while others cared for the injured victim. Approximately 30 minutes after the accident the buried victim's hand was discovered sticking out of the snow, about 20 m from the injured skier. Digging down the rescuers found the head 1 m below the surface. No signs of life were evident but resuscitation was attempted to no avail. Both skiers who were caught by the avalanche had been thrown about 30 m into the dense forest.
AVALANCHE
The avalanche, triggered by the skiers, started as a new snow slab 40 to 60 cm deep on a hard crust, then in the lower part of the path tore to the ground in a base of depth hoar. The avalanche started at an altitude of 2100 m and ran 150 m vertically. The crown had a width of 27 m and the track an average width of 14 m. The slope has a northeasterly aspect (in the lee of the prevailing winds) and an average . gradient of 38". The snow was deposited to a maximum depth of 1.5 m and a volume of approximately 600 m3. The snowpack in the starting zone consisted of 60 cm of depth hoar overlain by a strong crust overlain by 50 cm of soft new snow. No other avalanche activity was noted in the area at that time.
COMMENT
The chute where the accident occurred is outside the ski area, but is accessible rather easily from the top of the ski lift, and was not patrolled. Due to the popularity of powder skiing and advances in ski equipment such slopes prove to be attractive, which means that ski area operators must be aware of them and their avalanche potential. Observation, selective closures, and control are the best methods of protection. Experience in other areas has shown that permanent closures are difficult to enforce and are often violated unless the boundary is supported by a clearly defined geographic feature such as a ridge line or creeks. QUARTZ RIDGE, BANFF NATIONAL PARK, ALBERTA 27 MARCH 1977
One skier killed, four skiers injured
WEATHER
Observations at Sunshine snow study plot 2145 m ASL The accident site at Quartz ridge is about 5 km southeast of Sunshine Village
Temperature New Precipitation Snow Wind OC Snow Depth
Date Time Max Min cm mm cm km/h
23 March 0800 -2 - 7 1 1 122 S 13 1500 +1 - 6 3 1 125 S 10
24 March 0800 -1 -14 6 6 128 S 13 1500 -2 - 8 1 0.5 129 S 5
25 March 0800 -2 -17 T - - 125 S 19 1500 -4 - 10 T - - 124 S 23
26 March 0800 -4 -13 8 4 132 S 23 1500 -6 - 9 3 2 132 S23
27 March 0800 -5 -15 18 11 144 S 13 1500 -6 - 9 8 4 148 S 15
Moderate southerly winds were sustained all day 26 March and until 0100 h on the 27th. During the morning of 27 March whiteout conditions and heavy snowfall, with intensity greater than 1 cm per hour, prevailed at Sunshine Village. An unusually shallow and unconsolidated snowpack containing depth hoar and surface hoar together with the recent snowfalls had produced unstable conditions in the Rocky Mountains. The Wardens of the National Park had posted the avalanche hazard as being extreme and travel in avalanche areas was not recommended.
ACCIDENT SUMMARY
A guide with 20 guests registered at Sunshine Village at 0930 h on 27 March intending to hike on skis to Citadel Pass. At the park boundary they were to be picked up by helicopter and flown to Assiniboine Lodge. An additional 3 skiers tagged along with the party. The group left the ski area at about 1000 h and proceeded SSE along the alpine route for one hour. At about 1100 h the weather and visibility were extremely bad so the guide decided to take the party dolsn into the treed basin of Howard Douglas creek. A short time later, while crossing a short steep slope, one member of the party was caught in a small avalanche and carried down for approximately 30 m on the surface. He was unhurt and the group continued through the trees, stopping for lunch along the way.
At 1400 h the party reached an open area. Poor visibility limited the view of the slopes above. The guide skied approximately 15 m across the slope then suddenly noticed snow fracturing above and behind him. With a warning shout to the others he turned his skis downhill and escaped the avalanche. The main body of the avalanche, however, came from well above the group, ran over open slopes and through the trees where the majority of the party were located. The guide and the first two party members gained a safe position below a rock outcrop, but the avalanche hit seven skiers burying five of them.
RESCUE
After the avalanche had stopped the guide hurried back to his clients. He noted a ski tip in the snow, dug down, and uncovered a male survivor. After dispatching two persons to Sunshine for help the guide instructed others to probe with ski poles in likely burial areas. Three women were found almost immediately, buried against trees. They were conscious but suffering from shock and minor injuries. The guide located a fifth buried person with a probe 30 to 45 minutes after the accident. She was found by a tree under approximately 2 m of snow, exhibited no signs of life, and did not respond to artificial respiration. Lower down on the slope a fire was started and the injured survivors cared for.
At 1705 h the two messengers arrived at Sunshine Village and reported the accident. A rescue party was dispatched at 1745 h and travelling by oversnow vehicle and skiis arrived at the accident site at 1845 h. At 1900 h 13 of the survivors and a guide left via a safe route for a snowcat pickup and ride to Sunshine Village. At 2300 h some of the rescuers and able survivors left the site for the snowcat pickup while three rescuers, the four injured skiers and the deceased remained at the site overnight. At 0645 the next morning a helicopter carried the remaining persons to Banff.
AVALANCHE
The avalanche occurred at 2100 m ASL on a 'stepped' east facing slope, fractured to an average depth of 85 cm with a width of 300 m and ran approximately 320 m. The bed surface was likely surface hoar (Figure 19). There were three starting zones with slope angles varying from 36 to 3g0, and the average incline of track was 29'. The maximum depth of the deposited snow was 3.3 m. The rescuers noted numerous new natural avalanches in the valley when they flew out the morning after the accident. COMMENT
In a public inquiry held 5 August 1977 the jury determined the death as being accidental and made the following recommendations to prevent similar accidents.
- Two guides shall accompany a party of this size. - Electronic homing devices shall be carried for parties of commercial cross country tours. - All guides shall check the available avalanche hazard information. TEMPERATURE, "C
Figure 19 Snow profile at Sunshine Study plot on 28 March 1977 (Parks Canada)
LAKE LOUISE, ALBERTA 30 MARCH 1977
One skier killed
WEATHER AND AVALANCHES
Observations at Temwle study wlot 1975 m ASL
Temperature New Precipitation Snow Wind "C Snow Depth
Date Time Max Min cm mm cm km/h
26 March 0800 -3 -11 T 92 NW11 1530 -3 -9 1 0.2 92 W 22
27 March 0800 -3 -9 2 0.5 93 SW 11 1530 -6 -9 7 1.5 100 W 19
28 March 0800 -8 -18 2 1.5 102 Calm 1530 -3 -8 - - 100 N 4
29 March 0800 -2 -18 - - 100 Calm 1550 +2 -16 - - 9 7 N 9
30 March 0800 +2 -15 - - 97 NIV 25
The temperature at the time of the accident was 2OC and the sky was overcast.
Seven and three avalanches of significant size were initiated with explosives in the Lake Louise ski area 28 and 29 March, respectively. One of the 28 March avalanches occurred in the Flush Bowl and was small to medium sized in surface snow. No full depth avalanches were observed during the winter in the Flush Bowl.
ACCIDENT SUMMARY
At approximately 1215 h on 30 March two skiers traversed from the top of the Larch Chairlift to the Flush Bowl. They had made a run there earlier that morning with about thirty other skiers, all of whom had passed a "Danger Avalanche Area" sign and a "Ski Area Boundary" sign, before entering the bowl. After reaching the bowl one of the two men skied down, stopped at the bottom, and watched the descent of his companion. With a sudden yell the second skier came racing down the slope in front of an avalanche, which soon overran and engulfed him. Luckily the first skier was able to get out of the way. The time was approximately 1230 h.
RESCUE
The victim's companion watched the avalanche, saw the skier disappear, then skied to the nearest trail where he flagged down another skier who went to report the accident to the Lake Louise Ski Patrol. The companion returned to the avalanche site where he discovered the victim's hand on the surface. He began digging and had just exposed the head under 35 cm of avalanche snow when the ski patrol's first rescue party arrived at 1304 h. The victim was buried face up, was unconscious and not breathing.
The rescuers administered artificial respiration, but no response was noted. A doctor arriving on the site pronounced the skier dead; it was later determined that suffocation was the cause of death. The victim was evacuated by toboggan to a waiting ambulance.
AVALANCHE
The fracture line profile shows two weak, buried surface hoar layers and depth hoar. The slab avalanche fractured on the surface hoar 112 cm from ground (86 cm from the top), then removed the snow cover to its full depth further down the slope. A similar snow structure was observed in other parts of the Rocky Mountains in March 1977 and was the cause of other accidents and numerous natural avalanches.
The ski traverse is at an altitude of 2280 m and the fracture occurred approximately 60 m above that. The avalanche ran over a length of approximately 240 m with a maximum width of 80 m on a slope with a northwest aspect and an average gradient of 35'. The snow was deposited to a maximum depth of 2 m and the victim was buried approximately 13 m from the toe of the deposition.
COMMENT
The avalanche path had been treated with artillery fire two days before the accident and an avalanche was released, but obviously not all of the unstable srlow was removed. The area was not closed on the day of the accident but was posted with warning signs. Experience there and in other ski areas has shown that prolonged closures of attractive and readily accessible ski slopes are difficult to enforce. In such cases it is best to control avalanches by explosives, if necessary in repeated attempts with different targets, larger charges, and whenever the weather might have caused the snow stability to decrease.
If the victim's companion had made a hasty search of the avalanche deposit before going to report the accident he would have noticed the hand of the victim sooner and might have saved his life.
E OC TEMPERATURE, Y E a Ect m -12 -10 -8 -6 -4 -2 u m a I- Lrz> Z v, N Illllllllllll. -Wv, W l~l~l~'1~1~1'I- Z - ,,,3 r v, "> I=z ma 5 60 50 40 30 20 10 a=-- Z nE RAM RESISTANCE, kg - a - : 3 ", a u - X., - a CL Ern= a - X / "+ -0.5 -
Figure 22 Fracture line profile, observed on 1 April 1977 by Parks Canada MT. ATHABASCA, JASPER NATIONAL PARK, ALBERTA 7 SEPTEMBER 1977
Two climbers injured
WEATHER
Observations at Parker Ridge study plot 2030 m ASL
Temperature Precipitation Oc
Date Max Min. mm
5 September 10.5 0 20 (since 3 September)
6 September 11.5 -0.5 1.5
7 September 12 - 1 0.5
8 September 9.5 - 2 2
In late August and early September snow had started to accumulate at higher elevations on the Columbia Icefield. Overcast skies and intermittent snowfall prevailed on 7 September.
ACCIDENT SUMMARY
On 7 September two climbers ascended Mt. Athabasca (3465 m) via the standard route. Descending from the summit they walked roped up and when they traversed a slope parallel to the bergschrund at approximately the 2980 m level the leader was caught by an avalanche that came from Mt. Silverhorn. The second man was able to hold the rope until the leader was swept over the icefall, then he too was pulled off. The two climbers fell 15 to 20 m to the snow below and both were severely injured.
RESCUE
Other climbers in the campground noticed the absence of the victims and reported it to the attendant on the morning of 8 September. He in turn alerted a park warden at 0700 h. A rescue party of three left on foot immediately, reached the site at 0830 h, and immediately found the injured climbers who were suffering from multiple injuries and hypothermia. A helicopter dispatched from Banff arrived at the accident site at 0930 h and was able to land 25 m from the injured persons. The two climbers, one in serious condition, were then flown to the hospital.
AVALANCHE
The avalanche, starting as a loose snow avalanche, was not particularly large but was powerful enough to carry the leader down the slope over the icefall and then to pull down the second belay man. COMMENT
The two men were experienced climbers. During the night the less injured climber was able to keep the severly injured lead climber warm using massage and his own body heat. Had it not been for this action the first climber would probably not have survived the night. PRESIDENT'S COL, YOHO NATIONAL PARK, BRITISH COLUMBIA 9 OCTOBER 1977
One cl imbcr ki 1 led
WEATHER
During the late afternoon of 8 October a snowstorm deposited about 4 cm of new snow on top of the 2 cm already on the ground in the Little Yoho Valley. At higher elevations around President's Col an estimated 10 to 15 cm of snow fell. In the early morning of 9 October the temperature was below O°C and the sky was cloudy; there was a light snowfall and moderate southwest wind.
ACCIDENT
At 0700 hours on 9 October 13 climbers left the Alpine Club of Canada hut in the Little Yoho Valley intending to climb Mts. President and Vice President via President's Glacier and President's Col. At approximately 1000 h the first rope party of 3 climbers came to a large bergschrund about 175 m below President's Col. Shortly after the lead climber had crossed the bergschrund an avalanche released from above and swept him into the bergschrund where he was buried by the avalanching snow The second and third climbers were partly buried on the downhill side of the bergschrund.
RESCUE
The persons in the second rope party, who were close behind the lead climbers, came to the aid of the two partly buried persons, then following the rope began to dig for the climber buried in the bergschrund. Progress was extremely slow due to the lack of shovels, the loose snow, and the steep confining walls of the crevasse.
One climber left for help at 1230 h, and after hiking 11 miles and travelling 10 by vehicle he reported the accident to the park wardens at 1445 h. The first rescue party dispatched by helicopter at 1545 h arrived at the scene at 1600 h and a follow-up party at 1700 h. Buckets and shovels were used to remove the snow from the bergschrund and the victim was located 15 m down from the edge of the bergschrund at 1750 hours. He had died of suffocation.
AVALANCHE
The avalanche released at an altitude of 2430 m. It was a dry slab avalanche of new snow and fractured with a depth of 20 cm on old firn across a width of 10 m. It ran a length of 90 m on a 35" slope and deposited snow to a maximum depth of 10 m in the bergschrund. the avalanche was probably triggered by the lead climber. The slope had a northeast exposure and was in the lee of the southwest wind that prevailed during snowstorms.
COMMENT
This case demonstrates that a relatively small amount of new snow can produce dangerous avalanches on steep slopes of firn and ice, hence mountain climbers must be aware of avalanche hazards in the summer as well as in the winter. The hazard is magnified by crevasses that catch the avalanches and their victims.
The deep burial and slow digging because of the loose snow and confined space account for the long recovery time. Even if the climbing party had carried shovels the time would have been long and the survival chance of the buried person low. Due to the confined space in the bergschrund the park wardens found buckets were the most useful implement in removing the avalanche snow quickly and efficiently. WHISTLER MOUNTAIN, B.C. 8 MARCH 1978
Two ski patrollers buried
WEATHER AND SNOW
Weather observations were made at the Whistler Alpine study plot 1870 m ASL
Between 16 February and 6 March only 6 cm of new snow was recorded. On 19 February light rain formed a thin crust on the snow and between 25 February and 4 March low overnight temperatures and clear skies produced a substantial temperature gradient in the top 25 cm of the alpine snowpack and surface hoar on northwest, north and northeast slopes. During this period skiers noticed extensive audible snow settlement in untracked alpine back country.
A storm cycle began 6 March. In view of the unstable layers in the upper snowpack observers expected extensive avalanche activity. The snowfall continued 7 March and tapered off in the early morning hours of 8 March (Figure 23). Shovel tests and tilt board observations at 0800 h 8 March indicated a primary weakness approximately 60 cm below the snow surface in a layer of mixed surface hoar and immature temperature gradient crystals. No significant increase in the shear strength of this layer was measured between 0800 March 7th and 0800 March 8th, but the snow load increased considerably.
On 7 March small to medium sized avalanches were initiated with explosives on the northern and northeastern slopes and a small natural one occurred on a northeastern exposure. On 8 March medium to large sized avalanches were again released with explosives on the northwestern, northern and northeastern slopes.
ACCIDENT SUMMARY
Visibility was unlimited at 0845 h 8 March and the avalanche control supervisor decided to carry out a full avalanche control. Not only would the slopes within the ski area be controlled but also those of the surrounding terrain. The Gun 2 crew began to shoot at the slopes of Upper Harmony Bowl and Glacier Bowl at approximately 0930 h. By that time the visibility had deteriorated to variable and at times limited. Avalanches were released on northwestern and northeastern slopes though at times these were only heard rather than seen. Only one shot was fired into the Whistler Peak North Face area but the result could not be observed because the face was obscured by cloud. At approximately 1115 h six men departed from the top of the T-bar for the stabilization of the Surprise Shale and Whistler Bowl areas. At 1125 h the Surprise Shale team initiated a large avalanche on Surprise Path with hand charges. As the team climbed back on the lateral moraine below the North Face the four other patrollers were on the high traverse below the North Face, and when the last one of them had reached the middle of the slope an avalanche started above. The patrollers on the moraine below yelled a warning but two members of the group on the traverse were caught in the avalanche and were buried when it stopped. The time was 1130 h.
RESCUE
The patrollers not touched by the avalanche immediately called by radio for assistance. Because his arm was visible at the edge of the avalanche one of the buried men was found immediately and dug out. The two patrollers who had watched the accident from the moraine started a search with transceivers in the area where the second victim was last seen. His location was soon indicated by the transceivers then pinpointed by probing with a ski. Digging with their hands the patrollers found the victim under 1.2 m of snow. He was blue in the face and not breathing, but started breathing and gained consciousness quickly once his mouth was cleared of snow. At 1137 h a three-man party arrived with shovels and probes. The victim was freed completely with a large shovel and at approximately 1155 h a doctor, who was a member of the ski patrol, arrived and examined the victims. They were dispatched by helicopter to the Alpine Office where both of them recovered completely within a few hours.
AVALANCHE
I The slab avalanche started at approximately 2050 m ASL on a slope with a northerly aspect and 44" incline. The slab itself covered an area of approximately 4000 m2 and varied from 30 to 90 cm in depth. The avalanche ran 60 m vertically. The deposited snow had a maximum depth of 3 m but was spread over an area of about 5000 m2. COMMENT
I Control work at the Whistler High Traverse is usually attempted only during periods of good visibility. The single gun shot, too high on the slope, did not release an avalanche, therefore a second shot should have been placed lower on the slope, but poor visibility prevented the gun crew from assessing the result and so firing again. Undoubtedly the group traversing the "transition" area of the North Face triggered the avalanche, but the skiers were well spaced across the slope, therefore not all of them were caught.
Fortunately the victims were found quickly visually and with transceivers and ski probing and they could be dug out fast enough by hand. Nevertheless, avalanche control teams should not carry transceivers only, they should also have probes and shovels for quick recovery of buried persons. I - - - 1 AVALANCHE I - - ACCIDENT I - - I I - I I I 11:30
MARCH 6 MARCH 7 MARCH 8
Figure 23 Storm profile E w E E n m cn W- w 0 c uza + -> Z L + .Lux ,,, - Q W CZ* -- V) 3 u> s z WQ Z am-- ;am 0 was - W8* o x=m m a m C3
--420
-410
-- 400 -- 390 -- 380 4 + 1 \ GRAU PEL -- 370 -- 360 d CU -- 350
-- 340
-- 330 -- 320
-- 310
-- 300 -- 290 7 1 I I '~~f~/~~~CE -- DENSF" CONSOLIDATED 280 / SNOW TO THE GROUND I 1 I
Figure 24 Fracture line profile observed on 9 March 1978 SCENT ~uu~tFROM &+
Figure 25 View of the avalanche site (Photo C. Stethem) @ Location of buried patroller, found after 7 minutes x Location of patroller who was found immediately