The National Weather Service is working to hire back hundreds of positions laid off or otherwise cut by the Trump administration, but it’s progressing at a snail’s pace, forcing many offices to continue to cope with vacancies that could affect winter forecasts.

The National Weather Service warns that in addition to the extensive snow cover, these storms could cause blizzard and “whiteout conditions” from Tuesday through Wednesday and into Thursday, in some cases. These conditions, the NWS warns, could be dangerous for travel.

The NWS Wakefield VA issued a report at 5:05 p.m. on Tuesday for black ice until Wednesday at 9 a.m. for Northampton County.

Such events distort the polar vortex, which causes Arctic air to descend into the U.S. and causes temperatures to plummet.

The National Weather Service released an updated winter weather advisory at 8:52 p.m. on Tuesday valid from Wednesday 10 a.m. until Thursday 10 a.m. for Westmoreland Ridges, Fayette Ridges and Higher Elevations of Indiana.

A weather alert was issued by the NWS Newport/Morehead City NC on Monday at 9:53 p.m. for black ice until Tuesday at 9 a.m. The alert is for Northern Craven as well as Martin, Pitt, Washington, Greene,