With new snow and temperatures in the U.S. Northeast dipping well below freezing Tuesday, meteorologists have warned of a dangerous condition known as flash freezing that could make roads slippery and driving extremely dangerous. The phenomenon occurs when accumulated snow and slush is hit by a sudden blast of cold air, creating a layer of solid ice along roads and highways. When this happens, and if temperatures remain low, inexpensive ice-melting compounds often do not work, according to WVNSTV

Flash freezing occurs infrequently when conditions -- slushy snow accumulation followed by a sudden drop in air temperature -- are just right. City officials admonished drivers to stay off the roads. "[Commuters] are going to have a pretty difficult time when that slush freezes," Bill Simpson, a meteorologist with the National Weather Service, said Monday, according to CBS News. Officials said to expect hazardous road conditions and travel delays. Temperatures in parts of the Northeast were expected to plummet to between 10 and 15 degrees Fahrenheit by the afternoon.

Residents of Philadelphia, New York City and Boston awoke to roads covered in slush and snow after a winter storm dumped up to a foot of snow and sleet throughout parts of New York, Connecticut and Massachusetts on Monday. Parts of northern New Jersey recorded over 10 inches of snowfall, the National Weather Service reported. "What we have to do as New Yorkers is do the right thing, do the smart thing and prepare," New York City Mayor Bill de Blasio said Monday.

Some 2,400 pieces of snow removal equipment was deployed Monday night to clear streets and roadways of ice and slush, according to NBC New York. The dangerous conditions came a week after the Northeast was hit by so-called Winter Storm Juno, which blanketed the region in up to two feet of snow but was less intense than meteorologists predicted. The winter storm led to city officials in New York and Boston shuttering public transit systems and instituting mandatory driving bans.