The Swedish Environmental Protection Agency warned there was a “considerable” risk of large avalanches in the southern Jämtland, western Härjedalen and western Vindel mountains on Friday.
It urged visitors to exercise “careful snowpack evaluation, cautious route-finding and conservative decision-making”.
More than 800 avalanches were recorded in the areas the agency monitors during Sweden's 2017/2018 winter season. Two people, a snow mobile driver and a skier, then died in avalanche accidents.
In Norway a Swedish woman and three Finnish men were still missing a day after going skiing in the Tamok valley. Police fear they may have been swept away by an avalanche.
Also on Friday, national weather agency SMHI issued a class-one warning (the least serious on a scale from one to three) for icy roads in central and nothern Sweden.
The warning applied to Västerbotten, Jämtland, Västernorrland, Dalarna, Gävleborg, Uppsala, Västmanland, Värmland, Örebro, Södermanland and Stockholm counties.
Temperatures hovered between 5C and -5C on Friday from southern to northern Sweden.
In Norrtälje municipality fire stations kept their doors open overnight for residents who remained without electricity after Storm Alfrida battered the region on Wednesday.