Arizona Snowpack: Percent of Normal by Station

Q: How many snow stations does Arizona have?

23 active stations, of which 21 carry a 1991 to 2020 normal for a given calendar day and can therefore be given a percent of normal at all. They sit across 4 counties and 5 river basins, at elevations from 6,380 to 9,720 feet with a middle around 7,850. The highest is Snowslide Canyon at 9,720 feet. Every figure on this page states which of those two counts it was computed from.

Today, from the agency file

Where Arizona snowpack stands

Reading Arizona stations from the agency files…

Every instrument in the state

Arizona snow stations on the map

Reading the station map from the agency files…

Station by station

The Arizona stations, lowest first

A station is one clearing. It reads the snow lying on its own pillow, and that can differ sharply from a slope a mile away and a thousand feet higher. Reading one station against its own past is far more informative than reading two stations against each other, which is why the last column gives each one its own percentile rather than a rank against its neighbours.

Reading station readings from the agency files…

A snow telemetry station in a forest clearing with a tall instrument mast, a steel precipitation gauge and a fenced snow pillow, surrounded by conifers under snow — One station, which is what every row in the table below is. A clearing, a mast, a precipitation gauge and a fenced pillow on the ground. The clearing matters: put the same instrument under a canopy and the trees intercept a large share of the snow before it ever lands. “Cloud Peak SNOTEL site in Montana” — USDA Natural Resources Conservation Service — Public Domain

By river basin

Which Arizona basins are carrying the water

Arizona has very little of its own snow and a great deal of somebody else’s water. The Salt and Verde carry Arizona’s own mountain snow to Phoenix, while the Colorado carries snow that fell in Wyoming, Utah and Colorado, so the number that matters most to Arizona is measured in four other states.

The basin names below are the six digit hydrologic units the station records carry, named from the United States Geological Survey boundary dataset. Arizona covers 5 of them across 4 counties. A basin appears once three or more of its stations are reporting.

Against its own record

This day, across the Arizona record

A single percentage tells you where today sits against a thirty year median. It does not tell you whether that is unusual, and the two questions have genuinely different answers: a state can be at 70 percent of median in a year that is nowhere near its worst.

The water supply half, in the past tense

What the agency forecast for Arizona in 2026

This is the completed record of a finished season. The Natural Resources Conservation Service issues seasonal runoff volume forecasts for 12 points in Arizona, monthly through the winter and spring, and each issue supersedes the last. Below are the biggest of those points and how each forecast moved as the snow year revealed itself.

The current runoff forecast is published by the agency; the most recent issue shown here is months old by definition, because the series closes in early summer. For the forecast that applies now, go to the agency, or to NOAA Colorado Basin River Forecast Center for river stage.

Lake Powell Inflow

April 1 to July 31 runoff volume, thousands of acre feet. Normal for that period 6130. 7 issues on file for water year 2026.

01/01

01/16

02/01

02/16

03/01

03/16

04/01

normal 6130

The bar is the range the agency published at each issue, from the ninety percent exceedence value at the bottom to the ten percent value at the top, with the fifty percent value marked. An exceedence probability is the chance the actual volume exceeds that number, so ninety is the low end and ten is the high end. The fifty percent figure moved from 3620 on the January 1 issue to 1620 on the April 1 issue, or 59 percent of normal down to 26 percent. Those are the agency’s numbers for a season that has finished; the current forecast is on the agency’s own site.

Salt R nr Roosevelt

March 1 to May 31 runoff volume, thousands of acre feet. Normal for that period 179. 5 issues on file for water year 2026.

01/01

01/16

02/01

02/16

03/01

normal 179

The bar is the range the agency published at each issue, from the ninety percent exceedence value at the bottom to the ten percent value at the top, with the fifty percent value marked. An exceedence probability is the chance the actual volume exceeds that number, so ninety is the low end and ten is the high end. The fifty percent figure moved from 144 on the January 1 issue to 64 on the March 1 issue, or 80 percent of normal down to 36 percent. Those are the agency’s numbers for a season that has finished; the current forecast is on the agency’s own site.

Virgin R at Littlefield

April 1 to July 31 runoff volume, thousands of acre feet. Normal for that period 33. 4 issues on file for water year 2026.

01/01

02/01

03/01

04/01

normal 33

The bar is the range the agency published at each issue, from the ninety percent exceedence value at the bottom to the ten percent value at the top, with the fifty percent value marked. An exceedence probability is the chance the actual volume exceeds that number, so ninety is the low end and ten is the high end. The fifty percent figure moved from 31 on the January 1 issue to 18 on the April 1 issue, or 94 percent of normal down to 55 percent. Those are the agency’s numbers for a season that has finished; the current forecast is on the agency’s own site.

Verde R bl Tangle Ck ab Horseshoe Dam

January 1 to January 31 runoff volume, thousands of acre feet. Normal for that period 24. 2 issues on file for water year 2026.

01/01

01/16

normal 24

The bar is the range the agency published at each issue, from the ninety percent exceedence value at the bottom to the ten percent value at the top, with the fifty percent value marked. An exceedence probability is the chance the actual volume exceeds that number, so ninety is the low end and ten is the high end. The fifty percent figure moved from 23 on the January 1 issue to 35 on the January 16 issue, or 96 percent of normal down to 146 percent. Those are the agency’s numbers for a season that has finished; the current forecast is on the agency’s own site.

Gila R nr Solomon

January 1 to January 31 runoff volume, thousands of acre feet. Normal for that period 16. 2 issues on file for water year 2026.

01/01

01/16

normal 16

The bar is the range the agency published at each issue, from the ninety percent exceedence value at the bottom to the ten percent value at the top, with the fifty percent value marked. An exceedence probability is the chance the actual volume exceeds that number, so ninety is the low end and ten is the high end. The fifty percent figure moved from 14 on the January 1 issue to 12 on the January 16 issue, or 88 percent of normal down to 75 percent. Those are the agency’s numbers for a season that has finished; the current forecast is on the agency’s own site.

Blue Ridge Reservoir Inflow

January 1 to May 31 runoff volume, thousands of acre feet. Normal for that period 12.6. 2 issues on file for water year 2026.

01/01

01/16

normal 12.6

The bar is the range the agency published at each issue, from the ninety percent exceedence value at the bottom to the ten percent value at the top, with the fifty percent value marked. An exceedence probability is the chance the actual volume exceeds that number, so ninety is the low end and ten is the high end. The fifty percent figure moved from 10.1 on the January 1 issue to 9.8 on the January 16 issue, or 80 percent of normal down to 78 percent. Those are the agency’s numbers for a season that has finished; the current forecast is on the agency’s own site.

Volumes are in thousands of acre feet, in the units the agency publishes. Each point’s forecast period is printed above its chart, because the period is not the same everywhere: the Southwest runs off earlier and its forecasts are issued for an earlier window. Volumes from different periods are not comparable.

Reading the number

What the Arizona snowpack number shows

The peak date on this page is a median of medians. Across the 21 Arizona stations that publish one, the individual median peak dates span 64 days, from January 14 to March 19. A low station on a south face and a high one in a north facing cirque are in different climates, and averaging them produces a date that describes neither.

2 of the 23 Arizona stations have no 1991 to 2020 median at all, nearly always because they were installed too recently to have thirty years behind them. A station with no normal cannot be a percentage of one, so it appears on the map and in the table with its measurement and no percentage, and it is left out of the state total. The panel at the top of this page prints both counts.

The Lake Powell inflow forecast filed under Arizona describes runoff generated almost entirely upstream in the Upper Colorado basin. It appears here because that is where the agency files the forecast point, not because Arizona snow produces it.

How Arizona sits against the rest of the network. Its middle station is at 7,850 ft, against 10,275 ft in Colorado and 1,345 ft in Alaska. Elevation is not a proxy for depth: the deepest packs in the country sit on some of the lowest stations, because a maritime climate delivers far more water per storm than a continental one.

A wide brown river running high and fast between forested banks with the current carrying debris in the foreground — Snowmelt in a channel. Between the measurement above and the water here sit spring temperature, rain falling on snow, dust darkening the surface and how dry the soil was before winter. That gap is why this page publishes the measurement and links the agencies that publish the forecast. “Yellowstone flood event 2022 Lamar River above the Confluence with the Yellowstone River” — Yellowstone National Park (NPS) — Public domain

Where to go for the official answer

Who publishes Arizona water supply

Arizona Department of Water Resources

The state department responsible for Arizona water rights, active management areas and the state’s Colorado River entitlement.

Link checked 2026-09-04. The address is the department's own.

NOAA Colorado Basin River Forecast Center

The National Weather Service river forecast centre covering Arizona. River stage and flow forecasts are its product, and it is the place to look when the question is about a specific river rather than about snow.

Link loaded and answered on 2026-09-04.

Common questions

Arizona snowpack FAQ

When does Arizona snowpack usually peak?

Around March 2, taking the middle of the 21 Arizona stations that publish a median peak date. That is a median of medians and no single basin hits it: across the state those station level peak dates run from January 14 to March 19, which is 64 days of spread inside one state, driven almost entirely by elevation and aspect. The typical melt out across the same stations is March 27. All of these are medians drawn from roughly four decades of record and none of them is a statement about this year.

How many snow stations does Arizona have?

What is a normal Arizona snowpack?

In water rather than in depth, the middle Arizona station typically peaks at about 6.7 inches of water, and the deepest, Snowslide Canyon at 9,720 feet, typically peaks at 16.8 inches. Nationally the range across the 12 covered states runs from 6.7 inches in Arizona to 32 in Washington. A station’s own median is far more useful than a state one, which is why the table on this page gives every station its own.

Where does Arizona snowmelt go?

Arizona has very little of its own snow and a great deal of somebody else’s water. The Salt and Verde carry Arizona’s own mountain snow to Phoenix, while the Colorado carries snow that fell in Wyoming, Utah and Colorado, so the number that matters most to Arizona is measured in four other states. The basins on this page are the six digit hydrologic units the federal station records carry, named from the United States Geological Survey boundary dataset, and the largest of them by station count is Verde.

Who publishes the official Arizona water supply forecast?

The Natural Resources Conservation Service publishes seasonal runoff volume forecasts for 12 forecast points in Arizona, and NOAA Colorado Basin River Forecast Center publishes river forecasts; both are linked from this page. What this page shows from that programme is the completed 2026 water year record, in the past tense, with the issue date printed on every number, so you can see how a forecast moved across a season. On Lake Powell Inflow, the fifty percent forecast went from 3620 to 1620 thousand acre feet between the January 1 and April 1 issues, against a normal of 6130. For the current forecast, go to the agency.

Does this page tell me whether Arizona is heading into a drought?

No. Snowpack is one input to that question and this page publishes the input. The others are how dry the soil was before the snow fell, how fast the spring warms, whether rain falls on the snow, and how much dust settles on the surface and darkens it. Two identical Arizona snowpacks in two different years can deliver very different amounts of water for those reasons, which is precisely why the agency issues its runoff forecast monthly and revises it, as the 2026 arcs further down this page show rather than computing it once from a snow number. For Arizona drought conditions themselves, the United States Drought Monitor is the published record and it is a different measurement from this one.

Why do some Arizona stations have no percentage?

Two reasons, and the page distinguishes them. 2 of the 23 Arizona stations have no 1991 to 2020 median at all, almost always because they were installed too recently to have thirty years behind them, and a station with no normal cannot be a percentage of one. Separately, a station reporting exactly zero water against a normal of an inch or more is held out, because in this network that pattern is usually a failed sensor. Measured against the agency’s own quality flags for March 15, 2026, that rule held out 11 Arizona stations and the agency had independently flagged 9 of them as not valid.

How does Arizona snowpack compare with the rest of the West?

On elevation, Arizona’s middle station sits at 7,850 feet against 10,275 in Colorado and 1,345 in Alaska, and elevation is not a proxy for depth: the deepest packs in the country sit on some of the lowest stations, because a maritime climate delivers far more water per storm. On timing, Arizona peaks around March 2 against March 2 in Arizona and April 20 in Montana. The hub page puts all 12 side by side.

Bright sunlight on a high snow covered slope with dark conifers and a deep blue sky above the treeline — Strong sun on high country snow. At southwestern latitudes the sun does much of the melting directly, and a dusty snow surface absorbs far more of it than a clean one, which is one reason a southwestern pack can vanish faster than the air temperature alone would suggest. “Colorado 2013 (Breckenridge ski area)” by Jeff Gunn, CC BY 2.0

The same water, elsewhere on this site

Snow, melt and what happens after

Arizona droughtWhat the soil and the reservoirs already lost. Dry soil before winter absorbs melt that would otherwise reach a river.Arizona river levelsWhat this snow becomes, months later, at gauges on the rivers these basins feed.Arizona ski seasonWhether the snow is skiable, which is a resort question about groomed terrain rather than a water one.Mountain passesSeveral of these stations sit at passes, which is why the same instruments turn up on both pages.

Avalanche forecasts for the layers inside this same snowpack are issued by named forecasters at the avalanche centres: avalanche forecasts by state.

Sources for this page

USDA NRCS Air and Water Database, daily snow water equivalent filesfederal, public domain Read 2026-09-04.
One file per calendar day carrying every station’s entire period of record for that day. Measured at 102,474 bytes and 0.17 seconds for September 3 and 192,640 bytes for March 15, keyless and open to any origin. This is the source of every reading on these pages.
USDA NRCS Air and Water Database REST APIfederal, public domain Read 2026-09-04.
The documented API behind the same database. Used to build the station inventory, to verify that the daily files decode correctly, and as the fallback when the daily files cannot be reached.
USDA NRCS report generatorfederal, public domain Read 2026-09-04.
The one source that emits NRCS’s own labelled percent of median. Used to prove our figures reproduce the agency’s: all 118 Colorado stations matched exactly on value, median and percentage for March 15, 2026. Too slow to read live, at 8.9 seconds for one state.
USDA NRCS interactive station mapfederal, public domain Read 2026-09-04.
The agency’s own live map of every station it operates. This is where a reader goes for the official current picture, and every page in this vertical links it.
USGS Watershed Boundary Datasetfederal, public domain Read 2026-09-04.
NRCS station records carry a bare twelve digit hydrologic unit code and no name. The basin names on these pages come from the USGS boundary dataset, which named all 96 six digit basins in the station inventory.
California Department of Water Resources, California Data Exchange Centerstate agency, linked not reproduced Read 2026-09-04.
California’s own snow survey and the authority for California snowpack. Its data cannot be read from a browser on this site because it sends no cross origin header on any endpoint tested, including the preflight. It is linked rather than reproduced, and the California page explains where the two networks disagree.

Snow water equivalent measurements on this page are federal records collected by the USDA Natural Resources Conservation Service and are in the public domain. Percentages use the 1991 to 2020 normals period. The Arizona and basin totals are our arithmetic on those measurements and are not agency published indices. Water supply forecasts and runoff projections come from the agencies named above. Every state with a snowpack page →
Hero image: “Colorado 2013 (Breckenridge ski area)” by Jeff Gunn, CC BY 2.0