Two teenage boys reported missing Sunday night were found Monday, apparently killed by an avalanche on the Summit at Snoqualmie.

The boys, ages 17 and 18 are from Bellevue. They are not related to each other, said King County Sheriff’s spokesperson Ryan Abbott. One was an experienced snowshoer, and both were wearing avalanche beacons.

Although they were reported missing Sunday night at around 9 p.m.,searchers couldn’t begin to look for them until after the heavy snowfall and the avalanche danger was reduced, around 8 a.m. Monday.

“It’s so treacherous up there, at one point (Search and Rescue) had to stop the search and leave the area because of another avalanche,” Abbott said.

The two victims were found some at around 11 a.m. Monday, Abbott said and the avalanche was clearly the cause of their deaths. They were found with by the GPS signal on one of the boys’ phones.

The Sheriff’s Office urges anyone planning outdoor activity in the pass to check weather conditions before going. More snow is expected Monday night.