Summary of Western US SNOTEL Snow/Precipitation Update Report

Summary of Western US SNOTEL Snow/Precipitation Update Report

Based on Mountain Data from NRCS SNOTEL Sites

**Provisional data, subject to revision**

Data based on the first reading of the day (typically 00:00) for Wednesday, April 02, 2025

State/River Basin	Snow Water Equivalent		Water Year-to-Date Precipitation
State/River Basin	# of Sites	Percent of Median	# of Sites	Percent of Median
Alaska	23/62	80	45/62	112
Arizona	20/23	51*	17/23	49
California	32/32	107	32/32	106
Colorado	99/105	86	102/105	93
Idaho North of Salmon River	30/31	96	29/31	90
Idaho South of Salmon River	63/65	115	64/65	106
Montana	87/91	97	86/91	94
Nevada	30/32	126	31/32	114
New Mexico	21/21	15	21/21	64
Oregon	73/81	140	72/81	119
Utah	89/90	92	90/90	98
Washington	68/76	87	67/76	90
Wyoming	81/85	102	79/85	102
Arkansas River Basin	6/6	68	6/6	89
Colorado River Basin	103/108	89	104/108	97
Columbia River Basin	255/266	104	254/266	99
Missouri River Basin	45/48	98	44/48	96
Rio Grande River Basin	27/29	46	28/29	72
The Great Basin	104/105	104	105/105	104

-M = Missing data.
* = Analysis may not provide a valid measure of conditions.
N/A = Not available.

Footnotes for median and average:
(##) = If less than 30 years are available, this value specifies the number of years used for the median and average calculations.
Sites with less than 10 years available do not have medians or averages.

If the Basin Index (%) percent value is flagged as potentially invalid,
care should be taken to evaluate if the value is representative
of conditions in the basin.

The SNOW WATER EQUIVALENT represents the depth of water in the snowpack, if the
snowpack were melted, expressed in inches.

The WATER YEAR-TO-DATE-PRECIPITATION represents total precipitation since October 1st, expressed in inches.

Contact your state water supply staff for assistance.

Medians and averages are calculated for the period 1991-2020.

Provisional data, subject to revision.

* Site -- Either: (a) the current value is missing; (b) the median or average for the day is not available or is zero; or (c) for snow water equivalent, the median or average for the day is less than 10% of the maximum median or average value for the year.

* Basin - More than half of the stations for a basin with normals report missing or invalid data.

The basin index is calculated as the sum of the valid current values divided by the sum of the corresponding medians or averages and the resulting fraction multiplied by 100.