Winter Storm

National Weather Service's New Snow Squall Warning May Help You Avoid a Chain-Reaction Pileup

At a Glance

National Weather Service offices nationwide will be capable of issuing a new warning.
Several NWS offices tested these warnings last winter.
Snow squalls contain brief but intense snowfall rates that drop visibility and slicken roads.
The sudden change to poor weather conditions can lead to dangerous travel conditions.

The National Weather Service is expanding a new snow warning nationwide to convey the danger travelers face from an extreme reduction in visibility during short-term bursts of heavy snow.Beginning November 1, snow squall warnings can be issued by any NWS office when conditions warrant.

The warnings are somewhat similar to tornado, severe thunderstorm or flash flood warnings in that they will only cover a small area, typically only a few counties, and last for an hour or less.

An example of an NWS snow squall warning issued in March 2018. — An example of an NWS snow squall warning issued in mid-March 2018. Arrows were added to the polygon to show the direction the snow squall was moving.

Snow squalls have historically been a contributor to major highway pileups due to their brief but intense snowfall rates, dropping visibility quickly while slickening roads.

Snow squalls can occur in situations where there is no major large-scale winter storm in progress and may only produce minor accumulations.

"Annual highway fatalities from these events can exceed fatalities due to tornadoes in many years," the NWS said in its product description for the new snow squall warning.

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Seven NWS offices from Vermont to Wyoming had the capability to issue snow squall warnings last winter as a test before national implementation.

Four of those offices - Binghamton, New York, Burlington, Vermont, Cheyenne, Wyoming and Pittsburgh - issued at least one snow squall warning last winter.

The Federal Emergency Management Agency and wireless carriers are expected to transmit these snow squall warnings via Wireless Emergency Alerts to your smartphone at a future time.

A snow squall warning issued for your area will trigger the alarm on your NOAA Weather Radio.

(MORE: The Travel Danger of Light Snow)

For now, you won't see a scroll of a snow squall warning on TV via the Emergency Alert System, but that may change if there is interest from local emergency managers and broadcasters, according to the NWS service change notice.

Time series every 6-8 min from 2:59 pm to 3:20 pm of a snow squall in Hollidaysburg, Pennsylvania, Jan. 12, 2016. Credit: wunderground.com

The series of images above show an example of a snow squall in Hollidaysburg, Pennsylvania, on Jan. 12, 2016.

Notice how the visibility in the top two images of the series went from good to poor in about eight minutes. At the bottom right, you can see the visibility improve after the snow squall had ended about 13 minutes later.

(MORE: Weather-Related Car Accidents Far More Deadly Than Tornadoes, Hurricanes, Floods)

If a snow squall warning is issued for your area, the NWS has this advice:

Consider avoiding or delaying travel until the snow squall passes your location.
If you must travel, use extra caution, allow extra time and turn on your headlights
Rapid changes in visibility and slick road conditions may lead to accidents.