ALBERTA’S TOP 10 WHAT IS THE COSTLIEST HAIL STORMS ENVIRONMENTAL IMPACT? Seeding thunderstorms does not present Location Date Estimated Damage any environmental or health hazards In millions of dollars, and because silver iodide is a non-toxic normalized to 2011 dollars chemical at the concentrations used in ALBERTA SEVERE Calgary September 1991 1,281 cloud seeding. Silver is actually already Calgary August 2012 500 present in Canadian soil and many of our WEATHER Calgary July 2010 400 foods; it is also naturally found in our water Radar Station Edmonton July 1987 317 supplies. MANAGEMENT Calgary July 1996 139 In fact, the amount of silver iodide used for cloud seeding is minimal compared to SOCIETY Calgary July 1996 119 WHICH AREAS ARE the large quantities of water that storms Calgary July 1995 102 produce. Average seeding rates are about Calgary July 1998 86 PROTECTED? 10 grams per minute, which would be equivalent to putting a spoonful of silver Red Deer July 1991 59 Thunderstorms are seeded as they develop along iodide over the Niagara Falls every minute. Calgary July 1992 55 the foothills from the west of High River, all the way to Rocky Mountain House, AB. The seeding Rain samples collected from seeded Source: Public Safety Canada - Canadian Disaster Database aircraft follow the bigger storms as they move off Alberta storms have been found to contain (http://cdd.publicsafety.gc.ca/) the foothills and threaten communities. Priority is levels of silver similar to most surface and assigned to storms depending on their severity tap water supplies, and much less than and the size of the community. Only those storms what would be present in a cup of water threatening populated areas are seeded. stirred with a silver teaspoon.
FOR FURTHER INFORMATION HAIL SUPPRESSION CONTACT:
Dr. Terry Krauss Project Director [email protected]
Todd Klapak President [email protected]
Alberta Severe Weather Management Society c/o 128 Chancery Point Sherwood Park, Alberta T8H 1Z4
Severe Storm Rolling In ALBERTA HAIL STORMS: DID YOU KNOW? THE BREAKDOWN 2 3 Over 40 major hail In the months of June, July and 1 Silver iodide particles cause August, thunderstorms occur on storms rumble through Aircraft seed clouds with cloud moisture to freeze 55-75% of days. silver iodide particles Alberta every summer. and create ice crystals • Of these days, hail falls 50% of Ice crystals grow and the time Over the past decade, fall as rain/snow • 15% of the time that it hails, these hail storms have hailstones will be greater than the size of a walnut caused over $1 billion • Rainfall has been observed to in damage. increase minimally due to cloud seeding
WHO ARE WE? HOW DOES IT WORK? HOW IS IT CONDUCTED? WHO BENEFITS?
The Alberta Severe Weather Management Hail suppression works by seeding Cloud seeding is conducted with five twin- Cloud seeding has been found to reduce the Society (ASWMS) is a private, non-profit thunderstorms with billions of microscopic engine, high performance aircraft equipped to size/frequency of hailstones, which in turn organization that was established by the silver iodide particles. These particles act as dispense silver iodide. Three seeding aircraft reduces damage to people’s gardens, crops, Property and Casualty insurance companies artificial ice nuclei which freeze the supercooled are stationed at Springbank Airport and two homes, cars and businesses. of Alberta to administer the cloud seeding water drops in the storm’s updraft. are stationed at Red Deer Airport. Every year program. The actual cloud seeding operations from June 1st through to September 15th, these Cloud seeding also helps to control insurance are outsourced and performed under contract Seeding results in the formation of billions of aircraft remain on stand-by for immediate company losses, which in turn helps to stabilize by Weather Modification Inc. (WMI), a private additional ice crystals that compete for excess launch to seed storms. insurance rates throughout the province. atmospheric and cloud seeding company based cloud water, thus producing smaller ice particles. in Fargo, North Dakota. Many of these ice crystals melt completely as IS HAIL ELIMINATED? For these reasons, a hail suppression program they fall through warmer subcloud air on their makes good economic sense for everyone. WHAT IS CLOUD SEEDING? way down, but even those that don’t are still No, cloud seeding does not eliminate hail, but it significantly smaller than the “bruisers” that does reduce the size of hailstones which results Cloud seeding is a form of intentional weather smash windows, dent cars, and wreck roofs in less damage. modification that involves the process of and siding. dispersing a particular substance (we use silver iodide) into developing clouds. The intention is to alter the cloud’s micro-physical properties which results in a change of the type of precipitation that will fall.
Cloud Seeding Aircraft