Big Four Ice Caves Trail is an easy one mile hike. The route begins on concrete walks originally built by the Big Four Inn and continues through woods, crossing over the tumbling South Fork of the Stillaguamish River on a footbridge. Hikers enter a dense forest and just beyond the forest, visitors will see the ice fields and the immense north face of the 6,135 foot Big Four Mountain.
The ice caves are formed in the permanent ice of avalanche snow field during summer months. Melt water trickles down the mountainside and then channels under the ice. Warm air enters the crevices at the headwall and follows the path of the water. This combined action of melt water and warm air continues, thus eroding large tunnels in the ice.
BEWARE - the caves are very unstable and several people have been injured, or killed by collapsing Ice. DO NOT enter the caves.