January 21, 2016

A Dusting of Snow Is More Dangerous Than a Foot of Snow

Washington D.C. fell apart in the snow on Wednesday night. No, it wasn't the big blizzard everyone's freaking out about. A passing disturbance dropped an inch of snow, and not even an inch in some spots. Yet at midnight the traffic map still shows complete gridlock from Stafford County north into Baltimore, east to the Bay and west to Dulles Airport, hours after the snow stopped falling.

As we've seen time and time again from cities across the country, a dusting of snow is often more dangerous than a foot of snow. You're more likely to get stranded on the side of the road after an inch of snow than you are after a major snowstorm.

Think about the logistics of driving during or after a big snowfall. You'd have to make your way to your car, dig your car out, clean off enough to see, manage to get out onto the roads, and hope that every road between point A and point B is passable. This is plausible for people with large vehicles that are able to traverse somewhat deep snow, but most people have regular cars that would sit and spin their tires in snow half as deep.

Now consider a dusting of snow, sometimes not even deep enough to cover blades of grass or obscure the roadway. Most people facing this situation wouldn't hesitate to hop in their car, flip on their wipers for one cycle, and head out at highway speeds. When a light coating of snow—about an inch or less—falls during the day, schools and businesses will rarely grind to a halt. They'll let out at normal time and cancel after-school activities. Employers are unlikely to let their employees go home early. The day proceeds as normal.

This scenario usually leaves tens of thousands of cars flooding onto local roadways all at once at rush hour, casting their heat onto the fresh sheet of snow below. The heat melts the snow, which quickly freezes into a glaze of ice if temperatures are below freezing. Vehicles and ice don't mix. People spin out. People crash. People get stuck. All traffic on almost all roads slows to a crawl or stops altogether.

That is not a hypothetical. That is what happened in Washington D.C. on Wednesday. That is what happened in Raleigh the day of the infamous "flaming snow car" incident. That's what happened in Atlanta and Birmingham back in January 2014 when tens of thousands of people were trapped on the roads overnight after a quick couple of inches of snow came in a few hours earlier than forecast, forcing children to spend the night at school because buses and parents couldn't make it there to bring them home. It's not even an issue confined to the south or east—the beginning of winter, especially, brings regular stories of pile-ups in the northern U.S. from people not being used to the snow. Nobody is a good driver in the snow. You just get used to it.

We always hear after a plane crash that there's rarely one single cause behind the accident. The plane wrenched into the ground at 400 MPH because of a chain reaction of failures. Society crashes into a ditch for the same reason—it takes many converging factors in order for a disaster to unfold. Poor forecasts (which were not a cause in this instance) can contribute, as can poor judgement on the part of decision-makers, untreated roads, and people not being able to handle their multi-ton vehicles on a surface with no friction.

Trafficpocalypse 2016 will not happen again on Friday. A well-forecast event like the one expected to pound the Mid-Atlantic this weekend will prompt just about every school district and government in the line of fire to close their doors before the first cloud moves in. The grocery runs for those all-important milk sandwiches will go down in the hours before the storm. These large storms cause problems on another level—power outages, property damage, first responders delayed in answering calls, people not being able to leave home for a few days. But there's the key: people will stay home! 95% of the time, storms with appreciable accumulations of snow don't come as a surprise in this day and age, and people make appropriate plans to deal with it.

A dusting of snow doesn't command the same deserved level of respect as six or twelve or twenty inches of snow. Even though it seems embarrassing to admit in the face of so much ridicule from macho keyboard warriors, a dusting causes a unique set of problems you don't face in deeper snow. It doesn't matter what we should be able to handle, it matters how people and vehicles and roadways actually react with such small amounts of snow, and it's pretty hard to drive on the resulting sheet of ice.
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I graduated from the University of South Alabama in 2014 with a degree in political science and a minor in meteorology. I contribute to The Weather Network as a digital writer, and I've written for Forbes, the Washington Post's Capital Weather Gang, Popular Science, Mental Floss, and Gawker's The Vane. My latest book, The Skies Above, is now available. My first book, The Extreme Weather Survival Manual, arrived in October 2015.


  1. It took me 6 and a half hours to get home from work in Raleigh after that sheet of ice formed in 2005. I spent most of it sitting on US1. I have always been grateful I had enough gas in my car for a change.

    1. I saw the horror stories about US1 on the news. I was on Glenwood that afternoon! Saw the charred remains of the burning car.

  2. I've heard similar for when it just begins to rain as it mixes with the oils and dirt on the roadway, more slick than well into a downpour.

  3. For as baffled as people are that DMV drivers can't "handle" or "drive in snow", I'm just as baffled that people don't understand that it isn't, nor has it ever been an inch of snow in this area. It always, always turns into ice and that's why so many of the residents freak out, buy up as much as they can and slide all the way home: because we've slid across ice and don't do again. Call us when it's finally, truly melted.

    Thanks for the article, not enough scoffers will read it.

  4. Overconfidence in your vehicle and lack of patience definitely contribute. I know what my car can handle (not much) and adjust accordingly if I must drive with slowing down, increasing following distance, etc (and if it's significantly below the posted speed limit, I'm in the right with my hazards on). I've lost track of the number of times I've been aggressively passed then seen the SUV or truck in a ditch further down the road - and it usually is for a relatively small amount of snow. Tortoise and the hare, I suppose.


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