Sierra Nevada's First Big Snow of the Season Hits Tahoe and Yosemite This Halloween Weekend
A Pacific storm is burying the high Sierra under up to a foot and a half of snow this Halloween weekend — the season's first serious Western snowstorm — with ski-country snow spreading into Utah, Colorado, Idaho and Montana. Here is what's falling where, and how it stacks up against 56 years of October snow records.
Snow is flying in the Sierra Nevada for the first big time this season. The National Weather Service has Lake Tahoe, Yosemite and the mountain stretches of Interstate 80 and Highway 50 under Winter Weather Advisories from Saturday morning into Sunday, with up to 18 inches on the highest northern Sierra peaks and a foot or more across the Tahoe and Yosemite high country. It is the leading edge of a Pacific storm that is, at the same time, soaking the Southwest with rain.
A foot-plus of mountain snow in the last days of October is early, but our NOAA records show it is the kind of early that happens most years somewhere in the West — and in the Wasatch, it is simply routine. Below is exactly where the snow is landing, and how a late-October dump compares to 56 years of October data we pulled this week.
Where the snow is falling right now
This is one storm wearing two faces: heavy mountain snow on the cold side, flooding rain on the warm side. The National Weather Service forecast, as of Halloween morning, breaks down like this (snow is elevation-dependent — valleys stay wet, peaks get buried):
- Northern Sierra (NWS Sacramento): up to 10 inches above 7,000 feet, and as much as 18 inches on the highest peaks.
- Central & southern Sierra (NWS Hanford): 4 to 7 inches between 7,500 and 9,500 feet, up to 14 inches above 9,500.
- Lake Tahoe basin (NWS Reno): 2 to 5 inches, with up to a foot on the highest peaks, above 7,000 feet.
- Mono County / eastern Sierra (NWS Reno): 3 to 7 inches, up to 15 inches on peaks above 8,000 feet.
- Sun Valley & central Idaho (NWS Pocatello): 4 to 10 inches above 7,000 feet.
- Colorado high mountains (NWS Grand Junction): 5 to 10 inches above 10,000 feet, moving in Sunday into Monday.
- Southeast Alaska — Skagway (Winter Storm Warning): 9 to 14 inches with winds gusting to 40 mph.
Ski resorts in the Wasatch, the San Juans of southwest Colorado and Montana are all in line for the first meaningful snow of the year. And the warm flank of the same system is why the National Weather Service has Flood Watches up across southeast Utah, southwest Colorado and Arizona — 1 to 3 inches of rain onto ground still saturated from earlier October storms, which we cover in our Southwest flooding and West Texas flooding coverage.
Is a foot of late-October snow unusual? What 56 years of data say
We pulled the October snow record for nine Western stations straight from NOAA's daily archive. The short answer: at Sierra crest level and above, a storm like this is early-season, not extraordinary. Blue Canyon — the classic Sierra snow gauge perched at 5,286 feet right on Interstate 80 — averages about 4 inches of snow in all of October, and its biggest single October day in the record is 13.8 inches, set October 16, 1984. The highest peaks, several thousand feet above the gauge, routinely do far more.
Keep climbing and October snow stops being a novelty. In the Wasatch, Alta, Utah at 8,710 feet averages 27 inches of snow every October and has banked as much as 81 inches in a single October — more than the whole winter total for most of the country. Montana already got a taste: Bozeman logged a 6.9-inch snow day on October 11, 2026, our NOAA data shows — an early reminder that the Western snow season is already underway.
Western October snow, ranked by our data
Average October snowfall and the biggest single October day on record for each station, computed this week from NOAA GHCN-Daily (October only, 1970 onward). The “late-October” column — the biggest Oct 25–31 day — is the apples-to-apples test for a Halloween-weekend storm. Elevation decides everything: the valley cities at the bottom see almost nothing until later in the winter.
| Place (elevation) | Avg. October snow | Biggest October day | Biggest late-Oct day (25–31) |
|---|---|---|---|
| Alta, UT8,710 ft · Wasatch (ski) | 27.1" | 25.0" (Oct 31, 2004) | 25.0" (Oct 31, 2004) |
| Telluride, CO8,650 ft · San Juans | 7.5" | 11.0" (Oct 30, 1972) | 11.0" (Oct 30, 1972) |
| Blue Canyon, CA5,286 ft · Sierra (I-80) | 4.0" | 13.8" (Oct 16, 1984) | 6.5" (Oct 28, 1981) |
| Denver, CO5,286 ft · High Plains | 3.7" | 11.8" (Oct 24, 1997) | 10.1" (Oct 25, 1997) |
| Ely, NV6,250 ft · Great Basin | 2.5" | 8.7" (Oct 1, 2002) | 7.0" (Oct 30, 2000) |
| Flagstaff, AZ6,998 ft · San Francisco Peaks | 2.1" | 9.8" (Oct 28, 2004) | 9.8" (Oct 28, 2004) |
| Bozeman, MT4,431 ft · Northern Rockies | 1.8" | 6.9" (Oct 11, 2026) | 6.2" (Oct 31, 1973) |
| Salt Lake City, UT4,227 ft · Valley | 1.2" | 13.8" (Oct 18, 1984) | 8.5" (Oct 31, 1971) |
| Reno, NV4,405 ft · East Sierra foot | 0.3" | 3.7" (Oct 16, 1971) | 0.8" (Oct 31, 1978) |
Source: Weather On This Day analysis of NOAA GHCN-Daily daily snowfall (mm → inches), October only, bad readings excluded. “Avg. October snow” is the mean of annual October totals for years with complete reporting, 1970–2025; single-day records run 1970 through October 2026. Peaks above these reporting stations get considerably more. Figures are for the airport/primary stations and will differ from mountaintop ski-area totals.
The West's Halloween snow history
Trick-or-treat snow is a recurring act out West. A few that are written into our NOAA record:
- Alta, Utah — 25 inches on Halloween itself, October 31, 2004. That remains the biggest single October day in our Alta record. The same storm dropped 9.8 inches at Flagstaff, Arizona on October 28, 2004 — Flagstaff's biggest October day on record too.
- The Denver blizzard of October 24–25, 1997. Our data shows Denver took 11.8 inches on the 24th and another 10.1 on the 25th — nearly two feet in two days, one of the heaviest late-October storms the Front Range has recorded.
- Salt Lake City — 8.5 inches on Halloween, October 31, 1971. The valley's biggest Halloween snow in the record, even though SLC only averages about an inch and a quarter for the whole month.
- Telluride, Colorado — 11 inches on October 30, 1972. The San Juans are one of the few spots that can count on real October snow, averaging about 7.5 inches for the month.
For where and when the snow usually starts flying across the country, see our first-snow climatology for 18 cities and the full snowiest cities in America ranking.
Why this storm looks like El Niño
A single storm is weather, not a winter. But the shape of this one is worth noticing: heavy snow from the Sierra across the southern Rockies, flooding rain over the Four Corners, and a dry Pacific Northwest. That southern, storm-laden track is exactly what a strong El Niño tends to steer — and a strong El Niño is in place for winter 2026-27. We ran the snow numbers on that in does El Niño mean more snow, and laid out the region-by-region outlook in our winter forecast. The headline: the southern tier and central mountains lean snowier, the northern tier drier — which is one reason an early-season Sierra and Wasatch dump is worth watching rather than shrugging off.
What to watch next week
The advisories expire Sunday morning, but forecasters are already pointing at a second, potentially bigger Pacific storm aimed at the Western ranges in early November. For skiers that is the opening bell of the season; for the Southwest it means more rain on ground that cannot take much more. We will update this page with the observed snow totals once the Halloween-weekend numbers land in the NOAA record early next week.
How much fell where you are? If you measured snow in the Sierra, the Wasatch or the Rockies this weekend, tell us your town and your total — we fold real reader measurements into the recap. In the meantime you can check the odds of snow where you live with our snow day calculator, or dig into the all-time cold and snow marks on the Nevada, Utah, Colorado and California records pages.
Sierra Halloween snow, answered
How much snow will the Sierra Nevada get this Halloween weekend?
The National Weather Service forecasts up to 10 inches above 7,000 feet in the northern Sierra and as much as 18 inches on the highest peaks (NWS Sacramento), with 4 to 7 inches in the central and southern Sierra and up to 14 inches above 9,500 feet (NWS Hanford). Around Lake Tahoe, expect 2 to 5 inches with up to a foot on the highest peaks. Winter Weather Advisories run from 8 a.m. Saturday, Oct 31 to 7 a.m. Sunday, Nov 1.
Is it unusual to get a foot of Sierra snow in late October?
It is early but not rare. Blue Canyon, the classic I-80 Sierra snow gauge at 5,286 feet, averages about 4 inches of snow in all of October in our NOAA records, and its biggest single October day on record is 13.8 inches (Oct 16, 1984). A foot on the highest peaks in the last days of October is an early-season storm, not a freak one.
Which Western places get the most October snow?
Among places that report daily snow in our NOAA data, Alta, Utah, in the Wasatch leads by far — about 27 inches of snow in an average October, and as much as 81 inches in a single October. The San Juan mountains of Colorado (Telluride ~7.5 inches) and the high Sierra come next; valley cities like Reno (0.3 inch) and Salt Lake City (1.2 inches) see little until later.
Is this storm connected to El Niño?
A single storm is weather, not a season. But its shape — a wet, snowy storm track running from the Sierra across the Four Corners while the Pacific Northwest stays dry — is the pattern a strong El Niño tends to favor, and it is the pattern forecasters expect for winter 2026-27. The same system is dropping 1 to 3 inches of rain on already-saturated ground across the Four Corners.