SARAJEVO, Bosnia-Herzegovina — Stormy winds, rain and snow closed schools and left thousands of people without electricity on Friday in parts of Slovenia, Croatia and Bosnia. Bad weather also snarled traffic and blocked roads in the region.

Authorities issued weather alerts for dozens of municipalities in northern and north-western Slovenia as wind speeds reached 141 kph (87 mph) in some areas, public broadcaster RTV SLO reported.

A number of roads in the area were blocked with fallen trees as emergency crews worked through the night to clear the debris.

More than 15,000 people have been left without electricity in the affected areas. The RTV SLO report said “wintry” conditions, with snow have been reported even in some lower parts of the Alpine nation, in the south.

In neighboring Croatia, winds swept through the capital of Zagreb on Thursday afternoon and overnight, crashing trees, damaging city tram lines and roofs. Authorities there also suspended classes Friday in primary and secondary schools because of bad weather.

Photos on local media and social networks showed fallen trees in Zagreb, pulled out by their roots, some blocking streets or damaging parked cars. The wind occasionally reached up to 120 kmp (74 mph), meteorologist Petra Mikus Jurković said.

“Such lasting, strong, stormy wind is not common for the Zagreb area,” she said.

Elsewhere in northwestern Croatia, snowy conditions and winds have led to frequent traffic accidents, warned the country auto-club, or HAK, which monitors the road situation for drivers and provides aid if needed.

Similarly, roads in northwestern Bosnia were closed for heavy vehicles due to the snowfall. Problems with electricity supplies and snow have prompted local authorities to suspend school classes until the situation improves.

Experts say that extreme weather conditions can be linked to climate change.