The Big Four Ice Cave (trail No. 723) is a favorite two-mile round-trip hike, starting 26 miles from Granite Falls at the Big Four Picnic Area. The hike begins on boardwalks over a beaver-created marsh, then heads through a dense forest and across the South Fork of the Stillaguamish River to the ice caves and a view of 6,135-foot Big Four Mountain.

The caves—created when water channels under a small glacier—are generally exposed in late July and are visible through October.

Admire them from afar; the caves are very dangerous to enter because tons of ice may separate from the ceiling at any time, as happened in the summer of 1993 when the roof caved in on a young man but, miraculously, didn’t kill him. In winter and spring the snowfield is susceptible to avalanches.

Be aware that this area was badly hit by 2006 storms, and the main bridge leading to the ice caves was blown out. The Forest Service expects to rebuild in time for the 2009 hiking season. As of May 2009 the trail was closed. Be be sure to call ahead for details or check the US Forestry Service website for updates.