Another fast-moving dusting of snow could snarl the Friday evening commute, with a dangerous chill still not expected to lift until early next week.
The cold snap has already contributed to some deaths, state health officials said, though an exact count wasn't available.
An inch of snow that fell Thursday morning caused widespread crashes, and state highway officials are preparing for a similar situation Friday afternoon, though cautioned there is only so much they can do on crowded roadways and given the frigid weather.
"We'll be out there tomorrow in advance of any snowflakes falling, but if the pavement temperatures are this cold and the roads are clogged with people at rush hour, then it's about realistic expectations," State Highway Administration spokesman David Buck said.
On Thursday, meteorologists were looking at the possibility of what they call a "dry slot" forming over the region, a phenomenon that foiled snow Dec. 29. Two systems are expected to move into the area, one from the northwest and another from the southwest, and it's possible that winds high in the atmosphere could keep them apart, with dry air over Central Maryland, said Keith Krichinsky, chief operating officer of meteorology website Foot's Forecast.
Foot's is expecting about 1-3 inches across the region because of the relatively dry air, lower than expectations from others of isolated areas of up to 5 inches, Krichinsky said.
"It also has to do with how the storm picks up moisture from the ocean and the bay, if it wraps around a bit and slows down, that can affect it," he said. "A lot of dynamics go into these things."
Road crews are preparing for the possibility of snow causing a slippery commute, arriving sometime between 2 p.m. and 6 p.m. across the state, Buck said.
But Buck urged motorists to be prepared for driving in treacherous conditions. The low temperatures preclude crews from pretreating roads with a sprayed salt solution because when the pavement is that cold, even the solution would freeze, he said.
The spray helps prevent the first dusting of snowfall from sticking to the road, but anything heavier requires salting. Crews will be at the ready to treat roads within an hour or two of the snow's expected arrival, Buck said.
Temperatures are forecast to stay in the 20s through Friday, with wind
The cold weather has prompted the Maryland Zoo in Baltimore to close to visitors Friday.
The region could see its first above-freezing temperatures in five days over the weekend, though wind chills could keep things frigid until Monday. Highs are forecast in the lower and mid-30s Saturday and Sunday, around 40 on Monday and into the lower 50s by Tuesday.
The low temperatures continue to be a concern for health officials. Hypothermia was a factor in 11 deaths in Maryland through Monday, though any cold weather-related deaths that occurred in the sub-freezing stretch that began this week will not be included in a weekly state report until this coming Tuesday or later.
There have been several deaths involving hypothermia that the state medical examiner's office has reviewed this week, said spokesman Bruce Goldfarb. State health officials share information on cold weather-related deaths in reports released Tuesdays during the winter.
Hypothermia occurs when body temperature drops below 95 degrees, causing vital organs to shut down.
Thursday's snow, which measured 2 inches at