National Weather Service California Nevada River Forecast Center Department of Commerce National Oceanic and Atmospheric Administration National Weather Service

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WALKER RIVER - MASON AT SNYDER LANE (MASN2)
Latitude: 38.92º NLongitude: 119.19º WElevation: 4420 Feet
Location: Lyon County in NevadaBulletin Group: Eastern SierraRiver Group: Eastern Sierra
Monitor Stage: 9.0 FeetFlood Stage: 9.8 Feet
Please Note:Significant losses can occur in the Mason Valley upstream of the Mason stream gage. Increased forecast uncertainty exists in the long range forecast due to these unknown losses.
Observed Data Credit
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Raw streamflow data is provided by the US Geological Survey (USGS).
View USGS Data for this station location.

Historical Stage/Flow Data
Water Year
Peak Discharge (cfs)
Stage (feet)
Date
 Most Recent 5 Years
2023*
3,810
11.64
Jun 8, 2023
2022*
321
5.48
May 30, 2022
2021*
316
5.48
May 11, 2021
2020*
335
5.62
Oct 8, 2019
2019*
2,250
9.74
Jun 16, 2019
 Historical High Stage/Flow Events (Period of Record - April 1974 to Present)** - Ranked by Flow
1997*
3,900***
12.72
Jan 04, 1997
2023*
3,810
11.64
Jun 8, 2023
2017*
2,910
10.94
Jun 24, 2017
1995*
2,980****
11.57
Jul 11, 1995
1983*
2,790***
11.31
Jun 19, 1983
2011*
2,420
10.77
Jul 01, 2011
 * Discharge affected by regulation or diversion.
 ** Break in data between Oct 1984 and Sept 2010.
 *** Prior to Sep 30, 1984 - gage location 0.1 mile downstream at different datum.
 **** Estimated using other gages and MASN2 rating #5.1
Location Photographs
ESRI™ Locator Map
Impacts - E19 Information
9.0 FeetMonitor Stage, near bankfull conditions. No flooding in the Mason Valley-Yerington area.
9.8 FeetFlood Stage. Minor lowland flooding begins throughout Mason Valley-Yerington area with some inundation of lowlands and rural roads.
10.0 FeetMinor flooding of lowlands, pasture, cropland, and some rural roads throughout the Mason Valley-Yerington area. No flooding of structures of roads.
10.3 FeetMinor flooding of lowlands, pasture, and farmland in Mason Valley-Yerington area. Preventative sandbagging of lowest homes and businesses adjacent to river should begin if further rises are possible. Some flooding of rural roads.
10.5 FeetMinor flooding of lowlands, pasture, farmland, and some rural roads in Mason Valley. Preventative sandbagging of lowest homes in Mason and Yerington should be done as river rises, but limited flooding occurs. There may be some minor flooding of yards and basements in Mason.
10.8 FeetMinor flooding of lowlands, pasture, and farmland adjacent to the river throughout the Mason Valley-Yerington area. Some rural roads flood. Preventative sandbagging of low structures in Mason and Yerington may be necessary as river rises, but limited flooding occurs. Some minor flooding of basements and yards in Mason. Similar level to floods of July 1, 2011.
11.0 FeetModerate flooding of lowlands, pasture, and farmland adjacent to river throughout Mason Valley-Yerington area. Several rural and some secondary public roads flood. Yards and basements of lowest homes adjacent to the river in Mason and Yerington begin flooding. Preventative sandbagging is necessary. Possible damage to irrigation structures and levees. Similar to June 24, 2017 peak, and slightly higher than July 1, 2011 peak.
11.3 FeetModerate flooding of lowlands, farm, and pasture lands throughout the Mason Valley-Yerington area. Some low structures adjacent to river begin to flood. Several secondary and some primary roads flood. Exceeds flood peak of June 2017.
11.6 FeetMajor flooding of lowlands throughout the Mason Valley-Yerington area. Structures adjacent to river in floodplain may be damaged if not protected. Flooding of many secondary and some primary roads occurs.
12.0 FeetMajor flooding in the Mason Valley-Yerington area. Some portions of Yerington flood if breaches develop and the river spreads east. Many roads flood. Extensive flooding of farmland and pasture near the river flood.
12.5 FeetMajor flooding in the Mason Valley-Yerington area. Extensive flooding of farm and pasture lands. Many roads flooded. Some portions of Yerington flooded if breaches develop and the river spreads east.
13.0 FeetNear-record flooding in the Mason Valley-Yerington area. Significant flooding of homes and businesses in Yerington possible if breaches develop and the river spreads east. Extensive flooding of agricultural lands likely. Many primary and secondary roads flooded.
Official 7 Day National Weather Service Forecast   (NVZ001)
Tonight: Partly cloudy with a slight chance of showers and thunderstorms in the evening, then clear after midnight. Lows 47 to 57. Northwest winds 10 to 15 mph. Gusts up to 30 mph in the evening.

Wednesday: Sunny. Highs 71 to 81. Northwest winds 10 to 15 mph.

Wednesday Night: Clear. Lows 45 to 55. North winds 10 to 15 mph.

Thursday: Sunny. Highs 75 to 85. North winds 10 to 15 mph.

Thursday Night: Partly cloudy in the evening then clearing. Lows 47 to 57. North winds 10 to 15 mph.

Friday: Sunny. Highs 80 to 90.

Friday Night: Partly cloudy in the evening then becoming clear. Lows 52 to 62.

Saturday: Sunny. Highs 80 to 90.

Saturday Night: Breezy. Partly cloudy in the evening then clearing. Lows 50 to 60.

Sunday and Sunday Night: Clear. Highs 78 to 88. Lows 52 to 62.

Monday through Tuesday: Partly cloudy. Highs 84 to 94. Lows 55 to 65.
Product Disclaimer

This river graphic is not intended to serve as a substitute for official flood watches, warnings, advisories, or statements issued by the NWS Reno Weather Forecast Office. Observations are preliminary and subject to change. River levels identified as "forecast" should be consistent with those contained in official NWS products. River levels identified as "guidance" have significant uncertainty due to future weather or reservoir regulation and are provided for planning purposes only.