Terry’s Take: Double trouble, the historic Halloween storms of 1991!

Posted on: 10:11 pm, October 31, 2013, by

Terry Swails Weather Blog

This Halloween marked the 22nd Anniversary of two historic storm systems that greatly impacted various regions of the United States during the final days of October 1991. One was “perfect”, the other was an early season winter monster.

1991 PERFECT STORM….
The Perfect Storm has become part of pop culture after the release of the 2000 drama/thriller with the same name. But what exactly made it perfect? It was a combination of weather factors. A combination of a cold front emerging off the northeast United States coast, a developing non-tropical low pressure system near Atlantic Canada, Hurricane Grace spinning near Bermuda and a strong area of high pressure that stretched from the Gulf Coast to eastern Canada.

THE "PERFECT STORM" AT PEAK INTENSITY OCT. 30, 1991

THE “PERFECT STORM” AT PEAK INTENSITY OCT. 30, 1991

Even without any influence from Hurricane Grace, the area of low pressure that developed on October 28, 1991 east of Nova Scotia became quite the formidable storm system all by itself. After its “birth” on the Monday, the 28th, it quickly deepened further on Tuesday, October 29. As it did so, a strong area of high pressure was burgeoning over eastern Canada. This gave way to the development of a tremendous pressure gradient between the high and the lowering pressure of the gale center. The stronger the pressure gradient, the more fierce the winds…and this was a STRONG pressure gradient.

INTENSE PRESSURE GRADIENT RESPONSIBLE FOR HURRICANE FORCE WINDS

INTENSE PRESSURE GRADIENT RESPONSIBLE FOR HURRICANE FORCE WINDS

So again, even before any influence from Grace, winds were already increasing to sustained tropical storm-force near the center of the storm and along New England coast of the United States. Wave heights had been growing in size for two days and propagating toward the U.S. coast.

Then things got more interesting…

It was during the 29th when the large non-tropical low near Nova Scotia began to absorb Hurricane Grace; wrapping in its tropical moisture and likely receiving an injection of energy.

All the ingredients of The Perfect Storm were now in play. On the morning of Wednesday, October 30, the storm reached its peak intensity; the pressure lowered to 972 millibars. As it peaked in strength, the storm then began to drift southwest toward the New England coast on Wednesday and Halloween. Wind gusts exceeding hurricane-force lashed the New England coast on October 30 and 31. Powerful waves battered the East Coast. Tides rose to well above average levels and damage was extensive.

HALLOWEEN BLIZZARD OF 1991
As the Perfect Storm was perfecting its storminess along the New England coast, another (perhaps sometimes forgotten) major winter storm was raging across the Upper Midwest.

TRACK OF THE MIDWEST SNOW & ICE STORM

TRACK OF THE MIDWEST SNOW & ICE STORM

A blizzard of historic proportions was dumping feet of snow over the region with the state of Minnesota taking nearly the full brunt of the storm. The severe winter storm has come to be known as the Halloween Blizzard of 1991 or the Great Halloween Megastorm.

The path of this early-season winter storm was pretty remarkable. With The Perfect Storm acting as an atmospheric block on the East Coast, a track from west to east was a no-go. There was only one way to go for the Megastorm – north.

MINNESOTA SNOWFALL TOTALS

MINNESOTA SNOWFALL TOTALS

The storm first developed over the far western Gulf of Mexico on October 30. It strengthened and tracked nearly due north toward Minnesota and Wisconsin on Halloween and November 1. Its tropical moisture connection with the Gulf of Mexico allowed for plentiful available moisture and the resulting big snow totals.

SNOW TOTALS FROM THE NWS IN DULUTH MINNESOTA

SNOW TOTALS FROM THE NWS IN DULUTH MINNESOTA

The snowstorm set the largest single storm snowfall record for the city of Minneapolis; dropping over two feet of snow (28.4 inches). In Duluth, 37.9 inches of snow fell was the largest amount on record for the entire state of Minnesota – surpassing all snow totals from a single storm during any of the winter months! This record was later eclipsed by a lake-effect snowstorm on January 6-8, 1994 in which 47 inches fell over Finland in Lake County

Farther south, with warmer air nosing in, a major ice storm unfolded with southern Minnesota and the state of Iowa feeling the worst. From the La Crosse, Wisconsin National Weather Sercice: “1-2 inches of ice accumulated from southwest Iowa into north central Iowa and 2-3 inches of ice accumulated across south central and southeast Minnesota.”

Although many have forgotten this storm because of the attention being splashed on The Perfect Storm, those who lived it in Minnesota and Iowa will likely never forget. For more on the storm check out this link: http://climate.umn.edu/doc/journal/halloween_blizzard_20th.htm

1 Comment

Comments are closed.