Cold air comes down from far north, passes over open sea in the Bay of Bothnia, picks up moisture and releases it here in the form of snowfall when it reaches land, says Erik Höjgård-Olsen, duty meteorologist at SMHI.
It usually returns just in this area, along the Uppland coast, and can stretch quite far south.
In many places in Uppsala County, between five and ten centimeters of snow have fallen, and the snowfall is expected to continue until midnight.
Then this streak will shift eastward and pass over Stockholm County during the evening, but it doesn't seem to be the same amounts.
The snowstorm has led to several accidents. Over 20 people are on their way to Akademiska Hospital in Uppsala after multiple crashes on E4 and E18. The hospital has gone into emergency mode.
SMHI urges those who venture out on the roads to exercise caution.
Generally in such weather conditions, one should be prepared for the risk of poor visibility, risk of snowstorms, and, even if one considers oneself a superior driver, risk of problems on the roads.
