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 Thursday, May 02, 2024

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	29/62	119	48/62	102
Arizona	21/23	927*	19/23	101
California	32/32	106	32/32	96
Colorado	100/105	88	103/105	97
Idaho North of Salmon River	31/31	68	30/31	84
Idaho South of Salmon River	65/65	88	65/65	97
Montana	87/91	66	87/91	82
Nevada	30/32	116	31/32	116
New Mexico	21/21	57*	21/21	97
Oregon	77/81	102	77/81	103
Utah	89/90	102	90/90	109
Washington	68/76	67	67/76	88
Wyoming	82/85	87	81/85	100
Arkansas River Basin	6/6	73	6/6	94
Colorado River Basin	103/108	86	105/108	100
Columbia River Basin	261/266	77	260/266	92
Missouri River Basin	45/48	67	45/48	83
Rio Grande River Basin	28/29	58*	29/29	93
The Great Basin	104/105	107	105/105	107

-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.