March 2026 Northwest Storm: What the SNOTEL Data Actually Shows

A significant Pacific system moved through the Northwest between March 11 and 14, generating some of the largest 4-day accumulation totals of the season across the Washington Cascades and carrying real moisture as far inland as western Montana and central Idaho. The SNOTEL network recorded it all in real time. Here's what the data shows — accumulation, snow character, and what this storm actually did to the regional snowpack picture.

The Accumulation: Up to 49 Inches in Four Days

The storm's heaviest snowfall concentrated in the central Washington Cascades, where a corridor of stations between roughly 3,000 and 6,000 feet recorded totals that would be exceptional for any single event. Cayuse Pass (5,260 ft) and Pigtail Peak (5,800 ft) both topped the network at 49 inches over the four-day period. The bulk of that arrived on March 13, when those stations each recorded 25–26 inches in a single day — the storm's peak.

What made this event notable beyond the headline numbers was how low the snowfall extended. Tinkham Creek at 3,000 feet picked up 38 inches. Mount Gardner at 2,930 feet recorded 35 inches. Rex River and Lynn Lake, both under 4,000 feet, came in at 44 inches. A low freezing level kept snow falling at elevations where rain is more typical in March, pushing accumulation deep into the mid-elevation bands that skiers and snowmobilers actually travel through.

The storm also carried well inland. In the Bitterroot Range and northern Idaho mountains, stations at 5,800–6,400 feet recorded 35–44 inches — comparable to the Cascade totals but under noticeably colder temperatures, which matters for snow character.

Snow Density: What Kind of Snow Was It?

Raw accumulation tells you how much fell. Snow density — the ratio of snow depth to snow water equivalent — tells you what kind of snow it was. A ratio of 10:1 means ten inches of snow per inch of water content, which is classic dry powder. A ratio of 3:1 or lower is dense, wet, Cascade cement. Most Pacific Northwest storms land in the 4:1 to 6:1 range.

This storm came in at moderate density across the main accumulation zone. The top Cascade stations clustered between 3.5:1 and 5:1 — Cayuse Pass at 3.6:1 with temperatures holding in the upper 20s, Pigtail Peak at 3.5:1, Rex River at 4.3:1. That's denser than interior powder but well short of the soggy, high-water-content snow that weighs down roofs and collapses weak layers. For skiers, the mid-20s temperatures at the upper stations meant the new snow had real body to it without being unmanageable.

The lightest snow in the network fell at lower-elevation stations on the drier eastern side of the Cascades. Blewett Pass (4,240 ft) came in at 6:1, with temperatures near 29°F — cold enough for a drier snow but close enough to freezing that it wasn't true cold smoke. The densest readings came from a handful of high-elevation interior stations where existing dense snowpack and cold temperatures (sub-20°F) compressed the ratio toward 2.5:1 to 3:1, more a reflection of the base they were building on than the storm character itself.

What This Did to the Snowpack: Percent of Normal

This is where the data gets nuanced. The headlines said four feet of snow in the Cascades, which sounds like a season-saving event. The SNOTEL percent-of-normal numbers tell a more complicated story.

Among stations with at least 10 inches of current SWE — a reasonable threshold for meaningful comparison — the median Northwest station sits at 86% of the 1991–2020 historical average as of March 14. The mean is 84%. That's a deficit, but a workable one for mid-March. The storm helped.

The biggest beneficiaries were in Montana and the inland mountain ranges, where the storm arrived on top of a base that was already running close to normal. Harts Pass led the meaningful-SWE stations at 143% of normal with 57.1 inches of SWE — the storm pushed it well above its historical average. Stuart Mountain (126%), Hoodoo Basin (112%), and Badger Pass (123%) tell the same story: interior stations that were already decent came out of this event in genuinely strong shape.

The central Washington Cascades, despite recording the largest raw accumulation totals, mostly remain below their historical averages. Cayuse Pass got 49 inches in four days and is at 65% of normal. MF Nooksack received a similar total and sits at 67%. Stevens Pass is at 69%. Lyman Lake, which has some of the deepest snowpack in the Northwest at 47.5 inches of SWE, is still only at 89% of its median. These are stations that entered the storm carrying a significant deficit built up over weeks of below-normal snowfall earlier in the season. A four-day event, even a big one, doesn't erase that.

The Oregon Cascades are the most concerning part of the picture. The storm largely bypassed them. Mt. Hood Test Site sits at 47% of normal. Annie Springs is at 44%. Stations in the central and southern Oregon Cascades are running 20–40% of their historical averages, and this storm did little to change that. The OR snowpack picture will depend on what the rest of March and early April deliver.

The Takeaway

This was a real storm — meaningful accumulation, reasonable snow quality, and genuine improvement to snowpack deficits in the interior ranges. For Montana and northern Idaho, it was a genuinely good event that pushed many stations above their historical averages. For the Washington Cascades, it was significant but context-dependent: the raw totals were impressive, the percent-of-normal numbers are more modest. For Oregon, it was largely a non-event that leaves the season's water year concerns intact.

The next few weeks will be telling. March and April storms are the ones that determine whether a season finishes strong. The network will track every inch as it comes in.