Allentown, PA – Drivers across eastern Pennsylvania are being warned to prepare for flash freeze conditions developing Tuesday night into Wednesday morning, as temperatures drop sharply behind a departing storm system. The National Weather Service says lingering rain and snowmelt could freeze rapidly overnight, creating black ice on major corridors such as I-78, I-476, and Route 22.
A flash freeze occurs when air and pavement temperatures plunge below freezing within a short span, instantly turning wet or slushy surfaces into ice. These sudden freezes are especially dangerous on bridges, ramps, and shaded stretches, where road temperatures drop first.
On icy pavement, a vehicle traveling 35 mph may need up to 600 feet to stop — about six times the normal distance on dry roads. Motorists are urged to reduce speed, increase following distance, and avoid sudden braking during early morning hours.
“Even with clear skies, road surfaces can freeze fast after dark,” the NWS said in a Tuesday evening alert. “Expect slippery spots through the Wednesday morning commute.”
Drivers in Lehigh, Northampton, and Montgomery Counties should plan for slower travel and icy patches until late Wednesday morning as temperatures remain below freezing.
