The Swedish Meteorological and Hydrological Institute warned 10 centimeters (3.93 inches) of snow is expected to fall in the Stockholm area in the next 24 hours, and as much as 40 centimeters (15.75 inches) is possible in rural Gavleborg County.
"Combined with the wind, we could see snow drifts forming," Institute spokesman Emil Bjorck told the Swedish news agency TT.
More than 50 traffic collisions were reported in the Stockholm area by late Friday afternoon, "about twice the number of accidents we usually see on a Friday," said county police spokesman Sven-Erik Olsson.
Several ferry boats on the Baltic Sea, shuttling passengers between Stockholm and Finland, were delayed by large waves, the Silja and Viking Line ferry boat companies reported.
"We've seen five-meter (16.4 feet) waves," Viking Line's Johanna Boijer-Svahnstrom said about a boat whose arrival in port was delayed 6 hours.