U.S. DEPARTMENT OF COMMERCE LEWIS L. STRAUSS, Secretary WEATHER BUREAU F. W. REICHELDERFER, Chief TECHNICAL PAPER NO. 35 CliiDatology and Weather Services of the St. Lawrence Seaway and Great Lal~es Prepared by Marine Area Section, Offi~e of CJimatology WASHINGTON, D.C. 1959 For sale by the Superintendent of DocumeQts, U.S. Government Printing Office, Washington 25, D.C. - Price 45 cents TABLE OF CONTENTS Page Introduction ••••••..••••••••••.•••••.••••.•••••••••••••••••• • • • • • • • • · • . • • • • • 1 Acknowledgments ••••••••••••••••••••••••••••••.••••••.••••.••••••• · • . • • • • 1 General Description......................................................... 1 Climatology •••.•.••••..••••.••••••••••.••••••••••••••.•••••••••••• ••·• ••• ·•• 4 Cyclones ••••••••••••••••••.••••••••••••••••••••••••...•••••••• ··••••·••• 4 Winds •.•••••..•••..•••••••••••...•••••••••.••..•..••••.•••••.•••• • ...••• 12 Fog •..••• ' ••••••.•••••••• • •••••.•••••••••.•••••••.••.•.•.••..•••••.•.•.• 27 Air Temperature • . • • • • • • • • • • • • . • • • • • . • • • • . • • • • • • • • . • . • • • • • • • • • . • • • . 30 Humidity ••••••••••••••••••.•.•••••••••••.•.•••••..•..••.••• • • · • • · · • · · • · · 31 Precipitation ••••••••••••••.••.••••••••••.••.•••••.•••••.•.•••..•••.•.•. 34 Clouds ••••••••••••••••••.••••.•••••••••••••••••••••.••• "' .••.•• · • • • • • . • . • 36 Ice •.••.•••••.•••.••••••.••.••••••••••••..•••.....••••..•••.••••...••••• 36 Lake Levels •••••••••••••.••••••••••••.•••••••••••••.••••.••.••••• · . • • 40 Currents. • • • • • • • . • • • • • • • • • • • • . • • • . • • • • • . • • • • • • • • . • • • • • • • • • . • • • . • . • . • 41 Lake Temperatures •••••• ~ . • • • • • • . • • • • • • • • • • • • • • • • • • . • • • • • • • . • • . • • • • • • • . • 44 Weather Services. • • • • • • • • • • • . • • • • . • . • • • • • . • • • • • • • • • . • • • • • . • • . • • • • . • • . • . • • . • 4 7 Forecasting and Warning Services •••••••••••..••••••.•••••..••••••••..•.• 47 Small Craft, Gale, and Whole Gale Warning Displays •••.•••••••••.••••..•• 51 Weather Reports from Great Lakes Vessels ........................•.. ~ 53 Predicting Opening of Navigation •••••••••••• ~ •••.•••••..••••....•••••••• 53 References •••••.••••••••.••••.•••••••••••••.•••••..•••••••.•.••.•.• · • • • . • • • 54 Appendix~ •• • ••••••.••••••••••••..•••••••••. •". • . • • • . • • • . • • • . • • • . • • • • • . • • . • 57 Climatological Tables •••••••••••••••••••••••••••..••••• · ••• ••·•••••··••• 58 Warning Display Stations ••••••••••••••••••••••••••••••••• •••••••••·••••• 73 INTRODUCTION Completion of the St. Lawrence Sea­ Lakes and the St. Lawrence River area was way opens the Great Lakes to deep-draft, compiled in the Marine Section of the Office oceangoing vessels for the first time. of Climatology, U. s. Weather Bureau by This publication is intended to familiar­ Messrs. A. Cooperman, G. Cry, and H. Sumner. ize masters, mates, and steamship company The compilers are indebted to Dr. H. E. officials of vessels now plying the water­ Landsberg who was instrumental in initiating way and those who will, in the future, come the project and who has provided guidance to use the expanded facilities, with weather during preparation of the material. conditions and available weather services in the area. The elements described are primarily those affecting ship operations. Cooperation of the Meteorological Branch, Department of Transport, Canada, The area covered includes the St. in furnishing the climatological summaries Lawrence River from Quebec to Lake Ontario for Canadian stations, is gratefully ac­ and all the Great Lakes. Climatology of knowledged. the sea approaches to the St. Lawrence River and from the mouth of the river to Quebec can be found in U. s. Navy Hydro­ The assistance rendered by Mr. Roy L. graphic Office Publications No. 73 "Sailing Fox, Director, National Weather Records Cen­ Directions for Newfoundland" and No. 100 ter and his staff in processing the data, "Sailing Directions for the Gulf and River is gr~tefully appreciated. The Division St. Lawrence". of Forecasts and Synoptic Reports has pro­ vided material relative to radio broadcast Climatological tables for major ports schedules and related marine services. and a list of warning display stations The State Climatologists in the region appear in the appendix. A station location of the Great Lakes have surveyed their chart is shown in figure 1. areas of responsibility for pertinent material. Appreciation is also extended to Mr. W. w. Oak for his contributions ACKNOWLEDGMENTS on ice conditions. The material was pre­ This climatic summary of the Great pared for printing by Mrs. E. Lepp. GENERAL DESCRIPTION The St. Lawrence River system, com­ some 70 mi. wide, narrowing to 24 mi. at posed of an estuary and a chain of five Point des Monts, to 8 mi. at the foot of major interconnected lakes, forms a nat­ Orleans Island, and to 1/4 mi. near Quebec. ural transportation route from the sea The lower portion of the river, below almost 2000 mi. into the middle of the Quebec, is bounded on both sides by moun­ North American continent. The entire tain ranges. From Quebec to Montreal the system has a water surface area of over ·river averages 2 1/3 mi. wide, reaching 95,000 sq. mi., more than 8300 mi. of a maximum of 7 1/4 mi. in Lake St. Peter. shoreline, and a drainage area of some This lake is shallow but by dredging here 325,000 sq. mi. The region bordering and in other shoal sections a 35-ft. chan­ this great inland waterway is notable for nel is maintained from Montreal to the its industrial development and for the sea. The shores in this area are com­ magnitude of its natural and agricultural paratively low [2]. resources. From Montreal to Lake Ontario the The estuary of the St. Lawrence be­ natural river consists of a series of rel­ gins at the western end of Anticosti Is­ atively shallow lakes connected by rapids land, near 64°30'W. The river here is and shallows. The St. Lawrence Seaway soo 850 80° 750 50° 45° 1\) Ci!l ROCHESTER BUFFALO soo 850 80° 750 Figure 1. Station location chart of the St. Lawrence Seaway and Great Lakes. Project, undertaken jointly by the govern­ ceeding under the direction of the U. S. ments of the United States and Canada has Army Corps of Engineers to provide a 27-ft. provided a navigation control channel at channel throughout this entire area between least 450· ft. wide and 27 ft. deep, with Lakes Erie and Huron[l4]. a series of 7 locks 800 ft. x 80 ft. x 30 ft., giving a total lift of 225 ft. through Lakes Huron and Michigan are, in ef­ this section into the Great Lakes. The ma­ fect, only one lake. The connection through jor works constructed to provide this access the Straits of Mackinac is so broad and depth, which will make possible operation deep that no flow is perceptible between of some 80 percent of the cargo ships of the the two lakes and their surfaces stand at world in the Seaway are: 1) Lachine Canal the same level [12]. Lake Huron with a and Locks; 2) Beauharnois Canal and Locks; surface area of 23,010 sq. mi. and drain­ 3) Wiley~Dondero Ship Channel and Locks, age area of 72,620 sq. mi. is the connect­ Long Sault Dam and St. Lawrence Power Dam; ing link in the chain of the Great Lakes. 4) Iroquois Dam and Lock. It receives the waters of Lake Superior through the St. Marys River and those of Lakes St. Louis and St. Francis have Lake Michigan through the Straits of Mac­ also been dredged and some shoal areas in kinac. Lake Michigan has a surface area of the river cleared {14]. 22,400 sq. mi. and a drainage area 67,860 sq. mi. and is the only one of the lakes The upper St. Lawrence, west of completely within the United States. Iroquois, provides a natural channel of deep water through which navigation is The St. Marys River provides the con­ unrestricted to Lake Ontario. This east­ nection between Lakes Huron and Superior. ernmost lake of the Great Lakes chain is There are five locks, known as the Soo also the smallest, with a water surface area (or St. Marys Falls Ship Canal) Locks in of 7520 sq. mi. and a drainage basin of the river. Extensive dredging and con­ 34, 800 sq. mi. [11] • struction are being done in this region to provide a 27-ft. channel. The Weiland Canal provides the nav­ igation connection between Lakes Ontario Lake Superior, with a surface area and Erie across the Niagara Peninsula. of 31,820 sq. mi. and a drainage area of This canal is 27.6 mi. long with 7 locks 80,000 sq. mi. is the largest and deepest 800 ft. x 80 ft. x 30 ft. totaling 327 ft. (1302 ft.) of the Great Lakes, and, in fact, of lift. As a part of the St. Lawrence is one of the largest expanses of fresh Seaway project the Canadian government has water in the world [U] . dredged the canal to the 27-ft. standard depth [14] • The edges of the present Great Lakes embrace almost every type of shoreline Lake Erie is the second smallest of feature. Lake Superior is characterized the Great Lakes, with a water surface area by high and rocky shores along a large of 9930 sq. mi. and a drainage basin of portion of its coast. The shorelines of 32,490 sq. mi. In contrast to the other the other lakes are, in general, bordered Lakes, which have depths of at least 750 by flat plains which were portions of their ft., Lake Erie is shallow, reaching a max­ bottoms during the time when the great imum depth of only 210 ft., and over half continental glaciers formed their north­ the area is less than 100 ft. in depth. ern or northeastern shores. Sands of glacial origin, later modified by wave