Friday, January 27, 2017

Some meteorological insight into the Blizzard of '77 and what made it a storm for the ages..

There were 2 main aspects of the blizzard of '77. The first part was the initial cold front that plowed through that Friday morning Jan 28th bringing extremely high winds, plunging temperatures and snow that created the blinding whiteout conditions during the first 12 hours of the storm. This is what people remember as the start of the blizzard that paralyzed travel and stranded so many people that first day. The 2nd aspect of the storm was the persistent strong southwest flow that set up behind the cold front over the next 3 days that would continuously blow loose snow off snow-covered Lake Erie into southern Niagara and western NY resulting in extensive ground blizzard conditions persisting until the following Tuesday. ("Ground blizzard" is a blizzard that is mainly due to strong winds giving blowing snow off the ground, with no falling snow from the sky. Ground blizzards are common in the Arctic and Prairies, but are very unusual for Niagara or western NY) Those persistent winds also produced the incredible snowdrifts that buried cars, roads and houses and made travel impossible.

The National Weather Service in Buffalo did reasonably well forecasting the first part of the storm, i.e. the cold front.  The morning forecasts on January 28th warned of an intensifying storm system that would bring "very strong winds" later in the afternoon into the night with near blizzard conditions along with plunging temperatures. By 11 am, seeing how bad things were upstream, NWS BUF issued a blizzard warning for the first time in their history, warning of blizzard conditions developing by afternoon. Timing was a few hours off, but the weather office was forecasting blizzard conditions with very poor visibility in snow and blowing snow by the end of the day.

Regardless, thousands of people went to school and work that morning, not expecting anything severe until later in the day, if at all. In fact, the cold front sliced through Niagara by 1030 am and Buffalo by 11 am, resulting in instant blizzard conditions as southwest winds rapidly increased to 70 km/h (40 mph) with gusts to 120 km/h (70 mph). The blizzard hit so hard and so fast, that it was too late to send anyone home after it started. The whiteout conditions and severe drifting made travel almost impossible by midday, and things grew even worse as the afternoon wore on. Thousands of people were stranded where they were, including hundreds of school children as buses or parents couldn't get to them to bring them home. Any hope of improving conditions by the end of the day were dashed as the severe blizzard continued into the evening.

What forecasters didn't anticipate with this storm was the persistence of the severe blowing and drifting snow well after the cold front had passed. Normally, conditions would gradually improve a few hours after the cold front as winds eased or changed direction. In the case of the blizzard of '77, that didn't happen. The strong southwest winds remained virtually unchanged for 4 days, resulting in a prolonged ground blizzard well after the initial front had passed. This was an unprecedented situation for Niagara and western NY as ground blizzards are highly unusual in the normally mild winters in this part of the world. The prolonged ground blizzard just exacerbated the problems of the first day of the blizzard, resulting in increasing drifts and making rescue of stranded people more difficult as roads continued to be blocked for days instead of hours. Snowmobiles and 4x4 vehicles became the lifeline for so many people stranded by the storm.

In summary, the blizzard of '77 was a prolonged ground blizzard that was the result of persistent southwest winds off a deep snowpack on ice-covered Lake Erie. The deep drifts and poor visibility weren't the result of a major snowfall during the blizzard.. but rather 4 days of strong winds that continuously blew loose snow off frozen Lake Erie onto southern Niagara and western NY.  Given how mild winters have become, a repeat of such a scenario becomes less and less likely. But it's good to be aware of the circumstances that led to the Blizzard of '77 should such a freak winter occur again.  

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