An avalanche crashed down the Behrends Avenue avalanche path Friday morning, the largest that avalanche forecaster Tom Mattice has seen in his nine years in Juneau.

There was no major damage, besides a gate — which had a sign that warned of avalanche danger — being broken and a parked unoccupied van incurring light damage, said Mattice who runs the city’s urban avalanche advisory.

The avalanche was not unexpected, as Mattice raised the danger level for an avalanche to “high” on his forecast Wednesday night.

Due to the rain and humidity, avalanches have been tumbling down mountains in the borough’s backcountry. Every day, new snow and rainfall builds layers of wet and heavy snow above lighter layers of snow, which creates unstable conditions. Mattice compared the process to the spring of a mouse trap being pushed down more and more, gearing up for a release.

“Even though it’s harder to trigger (avalanches),” Mattice said, “they’re becoming more catastrophic in nature.”

Mattice said moisture has built up more than usual in the past week or so, with an inch of moisture at Eaglecrest Ski Area and three-fifths of an inch above the Mount Roberts Tram.

Conditions will likely remain unstable this weekend, Mattice said, and places such as The Flume and Perseverance Trail should be avoided as much as possible.

“Please use extreme caution this weekend if you’re playing in the mountains,” Mattice said.

An avalanche warning sign sits next to a metal gate destroyed by a Mount Juneau avalanche at the end of Judy Lane on Friday, March 31, 2017. (Michael Penn | Juneau Empire)