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, January 25, 2017

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	76	46/62	69
Arizona	21/23	188	19/23	171
California	32/32	197	32/32	239
Colorado	101/105	165	104/105	139
Idaho North of Salmon River	31/31	82	30/31	110
Idaho South of Salmon River	64/65	124	64/65	141
Montana	87/91	80	87/91	111
Nevada	29/32	193	31/32	191
New Mexico	21/21	161	21/21	137
Oregon	77/81	142	77/81	123
Utah	89/90	187	90/90	162
Washington	68/76	101	67/76	108
Wyoming	83/85	131	83/85	146
Arkansas River Basin	6/6	176	6/6	130
Colorado River Basin	105/108	171	107/108	150
Columbia River Basin	260/266	110	260/266	117
Missouri River Basin	45/48	82	45/48	116
Rio Grande River Basin	28/30	169	29/30	131
The Great Basin	103/105	191	105/105	196

-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.