National Park Road Closures: Mountain Pass Opening Dates

America's most famous scenic park highways—including Going-to-the-Sun Road (Glacier), Tioga Pass (Yosemite), and Trail Ridge Road (Rocky Mountain)—are closed by deep snow for six to eight months every year. Knowing historical opening and closing windows is critical to avoid planning a mountain road trip when passes are impassable.

Key takeaways

• Going-to-the-Sun Road (Logan Pass, 6,646 ft): Typically opens late June to early July; closes to through-traffic the third Monday in October.
• Tioga Road (Tioga Pass, 9,943 ft): Typically opens late May to late June; closes following the first major winter storm in November.
• Trail Ridge Road (Alpine Pass, 12,183 ft): Aims for Memorial Day weekend opening; closes seasonally in mid-to-late October.
• Rim Drive (Crater Lake, 7,100 ft): West Rim typically opens mid-to-late June; East Rim opens early-to-mid July; closes November 1.
• North Cascades Highway (SR 20, 5,477 ft): Closes late November to mid-December; reopens mid-to-late April.

Major high-elevation mountain passes: Historical opening and closing dates

High mountain passes traverse harsh alpine tundra where winter drifts exceed 30 to 50 feet. Snowplow crews deploy heavy rotary blowers and bulldozers for weeks to clear these corridors. Here is the historical operational data:

• Going-to-the-Sun Road — Glacier National Park, MT: Earliest modern opening: June 13; latest opening: July 13. Average opening date: June 28. Seasonal closure over Logan Pass is scheduled for the third Monday in October, though sudden early blizzards can temporarily close the pass in September.
• Tioga Road (CA-120) — Yosemite National Park, CA: Connects Yosemite Valley to Lee Vining and Mono Lake across Tioga Pass (9,943 ft). Earliest opening: May 2; latest opening (after heavy snow winters): July 22. Average opening: late May to early June. Typically closes in November.
• Trail Ridge Road (US-34) — Rocky Mountain National Park, CO: Reaches 12,183 feet, making it the highest continuous paved highway in North America. NPS road crews target Memorial Day weekend (late May) for opening. Closes seasonally between mid-October and early November.
• Rim Drive — Crater Lake National Park, OR: Crater Lake receives an average of 42 feet (500+ inches) of snow per winter. West Rim Drive usually opens by mid-to-late June; East Rim Drive and the Pinnacles spur road open by early-to-mid July. Both close on November 1.
• Lassen Park Highway (CA-89) — Lassen Volcanic National Park, CA: Traverses the shoulder of Lassen Peak at 8,512 feet. Typically opens in late June or early July and closes after the first major storm in November.

How winter snowpack dictates spring opening schedules

Spring opening dates are not predetermined calendar deadlines; they depend strictly on snow water equivalent (SWE) measurements recorded by regional SNOTEL automated weather stations. In heavy snowpack years (such as 2017 and 2023 in the Sierra Nevada), passes require extensive avalanche blasting and rockfall mitigation before plows can safely cut road lanes.

If you plan an early-season road trip in late May or June, always check active plow progress reports published weekly on park websites, and keep lower-elevation detour routes ready. For tips on route flexibility, see our multi-park road trip planning guide.

Frequently asked questions

Can you drive Going-to-the-Sun Road in June?

You can always drive the lower sections from West Glacier to Avalanche Creek or from St. Mary to Rising Sun. However, the high alpine section across Logan Pass rarely opens before the final week of June or first week of July.

What happens if an unexpected snowstorm closes a mountain pass during my trip?

Mountain parks issue temporary closures that can last from several hours to a few days while plows clear ice and slush. Always carry warm layers, check the park's official road status line each morning, and ensure your vehicle has adequate fuel for lengthy detours.

Is tire traction or snow chains required on mountain passes?

Yes. During shoulder seasons (September–October and May–June), state highway patrols and the NPS can mandate tire chains or 4WD/AWD with snow-rated tires (M+S or 3PMSF) during active storms.