Lably
Skip to content

Blizzard of 1977

Deadly blizzard in New York, US, and Ontario, Canada

  • 39 min read
  • 6 chapters

Related on Lably

Through Standard deviation

Certain pre-existing weather conditions exacerbated the blizzard's effects. November, December and January average temperatures were severely below normal. Lake Erie froze over by December 14, 1976; when this occurs, lake-effect snow does not occur because the wind cannot pick up moisture from the lake's surface, convert the moisture to snow, and then dump it when the winds reach shore.

Lake Erie was covered by a deep, powdery snow; January's unusually cold conditions limited the usual thawing and refreezing, so the snow on the frozen lake remained powdery. The drifted snow on roadways was difficult to clear because the strong wind packed the snow into a solid state. In addition to the roads becoming impassable, motorists had to deal with vehicles breaking down due to the combination of very cold temperatures, very high winds and blowing snow.

In the hardest-struck areas, snowmobiles became the only viable method of transportation. In Western New York and Southern Ontario's Niagara Peninsula, snow which was accumulated on frozen Lake Erie and snow on the ground at the start of the blizzard provided ample material for the high winds to blow into huge drifts. The combination of bitter cold, high winds, and blowing snow paralyzed areas affected by the storm. Lake Ontario rarely freezes over, which meant northern New York had to deal with considerable lake-effect snow. Coupled with the existing snow cover and wind, this had a similar effect.

Winter of 1976–1977

Weather conditions during the months leading up to the blizzard contributed to the disastrous storm. A high-amplitude planetary wave pattern set up, which was very persistent from October 1976 through January 1977, and involved a ridge over western North America and a trough over eastern North America. In January 1977, this pattern persisted, with the pressure of the strong ridge over western North America being more than two standard deviations from the mean, while the strong trough centered over eastern North America was more than three standard deviations from the mean.

A strong blocking high developed over the Arctic Ocean during January, and this moved the polar vortex to southern Canada, south of its normal location. Strong northwest flow between the ridge and the trough resulted in a strong northwest flow in between, which ushered Arctic air into the central and eastern United States. The circulation helped cause record cold for the winter over many portions of the eastern United States, with the Ohio Valley averaging more than 8 °F (4 °C) below normal. The severe winter was not limited to the northeastern United States; snow was observed in Miami, Florida, on January 20, and snow mixed with rain occurred in the Bahamas. In contrast, Alaska was exceptionally mild: Anchorage averaged 20.2 °F or 11.2 °C above normal and was in fact 2.5 °F or 1.4 °C warmer for the month than Atlanta half the distance from the equator, whilst it was the warmest January since at least 1937 for the whole state except the North Slope and the Aleutian Islands. The Pacific Northwest, located under the strong ridge, experienced unprecedented drought, with all 29 climatic divisions of Washington, Oregon and Idaho experiencing their driest October to February period on record.

Sign in to keep reading

5 more chapters are free with a Lably account.

More in Earth science