The Knox family of Florida was more than delighted by the scenery near Silverton, but they were stunned by the avalanche destruction they saw during a tour with Silverton Rock Pirates. They said it felt similar to hurricane damage. (Nina Riggio, Special to The Colorado Sun)

SILVERTON — The Hardrock 100 ultrarun through Colorado’s southwestern mountains has been canceled because of this year’s heavy snowfall and avalanche debris.

In an announcement Monday, Hardrock Hundred Endurance Run director Dale Garland said that conditions on much the 100-mile course through the San Juan Mountains are uncertain.

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While snow looked to be dropping to manageable levels in time for July’s race, Garland said that unprecedented avalanche debris and high levels in waterways helped lead to the decision to cancel what would have been the 26th run.

The race was also called off in 2002 because of wildfires and in 1995 because of heavy late season snow.

Runners from around the world participate in the race over 13 mountain passes. They run through the night and finish in an average of around 41 hours.

This is the second ultra run in the San Juans to be canceled. The San Juan Solstice, a 50-mile race run from Lake City, was canceled in May.