Seasonal closure · SH-21 · Idaho
Closes when avalanche danger is high, with no fixed dates. Reopens once the snow settles. Below: what the 511 Idaho feed is posting for SH-21 right now, and the dates ITD gives, quoted from its own page.
“State Highway 21 from Grandjean to Banner Summit. The highway will reopen when the snowpack has stabilized and the risk of active avalanches is reduced.”
Source: itd.idaho.gov/sh-21, read October 2, 2026.
Idaho's DOT traveler site. The list of record for closures, restrictions and detours.
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No fixed date; avalanche-triggered That is what ITD publishes, read October 2, 2026. The gate goes in when the snow does, so the date moves from year to year. Closure is avalanche-driven, not a fixed seasonal date.
Reopens when snowpack has stabilized Plowing and avalanche work set the day, and the agency announces it when the road is ready.
Grandjean to Banner Summit (about 11 miles, around 70 avalanche paths). The rest of SH-21 is handled like any other road in Idaho.
511 Idaho is the official source for the state highway. The block at the top of this page reads the same 511 Idaho feed every five minutes and lists what is posted for SH-21. If the feed cannot be reached, the page says so instead of showing an empty list.
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