When it comes to Pennsylvania, we tend to see wintry weather anywhere from October through April, with the greatest impact typically during the months of January, February, and March. Snow, sleet, ice, heavy rain, cold, wind, flooding, and ice jams can all impact Pennsylvania during winter.
Winter weather preparedness is important to keep you and your family safe during our coldest season.
Know Your Terms
The National Weather Service (NWS) uses a lot of winter terms, what are the differences among them? The terms “Winter Storm” or “Winter Weather” are all-encompassing for storms containing snow, ice or both, and are the most common set of terms you will see during Pennsylvania winters.
Freezing rain covers general icing, while ice storm is reserved for significant ice accumulations that can produce major and widespread damage to property, trees, and utilities.
Blizzard is reserved for a storm with blowing snow and strong wind lasting at least three hours (it does not have to be actively snowing for a blizzard).
Snow squalls are small, short-lived, bursts of snow and wind which reduce visibility and slicken roadways. Wind chills and damaging non-storm winds are sometimes dangerous too during the winter, and can result in special NWS alerts.
Frost/freeze alerts are issued around agriculture and growing season. Of course flooding from snowmelt, heavy rain, or ice jams and severe weather alerts can be mixed in on rare occasions.
We even had several tornadoes in recent years during February!
What is a snow squall and why is it a big deal?
Snow squalls are not new, but our understanding of what causes them and how dangerous they can be to drivers has improved drastically in recent years.
Similar to a thunderstorm, a snow squall is a brief and intense storm moving quickly and covering a small area. Snow squalls create instant whiteout, blinding conditions while quickly slickening the roadway. Drivers often go from clear, sunny, cold weather on dry pavement into a wall of white, icy roadways in a matter of seconds. Numerous multi-vehicle accidents have occurred on Pennsylvania interstates over the years because of snow squalls, with limited warning to drivers.
The NWS has worked to better predict days when squalls may occur to allow drivers to adjust travel plans in advance. Leading up to a squall, a “Snow Squall Warning” may be issued by the NWS to alert drivers.
The best course of action is to delay or avoid driving on squall days. The second best is to plan your travel and include methods to receive the snow squall warnings on your route in order to pull off at an exit and avoid them. The only safe place during a squall is off the roadway, because once you enter one, there is no refuge.
Learn more about snow squalls and what actions to take.
What are the different alerts that NWS issues for winter weather?
The NWS will issue a few different alerts for winter weather hazards, including winter storm, ice storm, freezing rain, wind chill, blizzard, and snow squall. Each of these hazards are unique, but all should be taken seriously.
A few days prior to an event, the NWS may issue a watch when the ingredients are coming together for winter weather, but the confidence and details are still a bit uncertain. Closer to a winter weather event, an advisory or warning may be issued.
An advisory is issued when wintry weather is likely, but is more of an inconvenience, nuisance, or a disruption.
A warning, the most serious alert, is issued when wintry weather is likely and may be a threat to life and property. You can receive these messages on TV, radio, weather radio, phone or email. Be sure to visit AlertPA to sign up for notifications.
The NWS will issue alerting products based on confidence and threat level. An outlook is issued several days in advance when confidence and threat details are lower. A warning is issued very close to the weather event when confidence and threat significance are both high.
To learn more about winter terms, safety, and preparedness, explore the NWS website, PennDOT website, and Ready PA website.
Also follow Ready PA on Facebook and Twitter and check the hashtag #PAWinter for timely graphics and messaging.