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 (MASN2)
Latitude: 38.92º NLongitude: 119.19º WElevation: 4420 Feet
Location: Lyon County in NevadaRiver Group: Eastern Sierra
Monitor Stage: 9.3 FeetFlood Stage: 9.8 Feet

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
2016
371
5.51
May 9, 2016
2015
361
6.41
Jul 11, 2015
2014
227
5.81
Jun 1, 2014
2013
347
6.24
Jun 5, 2013
2012
337
6.23
Apr 30, 2012
 Historical High Stage/Flow Events (Period of Record - April 1974 to Present)*
1997
3,900**
12.72
Jan 04, 1997
1995
2,980**
11.57
Jul 11, 1995
1983
2,790***
11.31
Jun 19, 1983
2011
2,420
10.77
Jul 01, 2011
 * Break in data between Oct 1984 and Sept 2010.
 ** Calculated using other gages and MASN2 Rating #2.
 *** Measured stage converted. Crest calculated using MASN2 Rating #2.
Location Photographs
ESRI™ Locator Map
Official 7 Day National Weather Service Forecast   (NVZ001)
Today: Partly cloudy. Isolated showers and thunderstorms in the afternoon. Haze in the afternoon. Highs 88 to 98. Light winds.

Tonight: Partly cloudy. Isolated showers and thunderstorms in the evening. Haze in the evening. Some thunderstorms may produce heavy rainfall in the evening. Lows 58 to 68. East winds up to 10 mph.

Monday: Partly cloudy in the morning, then mostly cloudy with a slight chance of showers and thunderstorms in the afternoon. Highs 85 to 95. Light winds becoming southeast around 10 mph in the afternoon.

Monday Night: Mostly cloudy with a slight chance of showers and thunderstorms in the evening, then partly cloudy with a slight chance of showers after midnight. Lows 61 to 71. Southeast winds 10 to 15 mph.

Tuesday: Partly cloudy with a slight chance of showers in the morning, then mostly cloudy with a chance of showers and thunderstorms in the afternoon. Some thunderstorms may produce heavy rainfall in the afternoon. Highs 82 to 92. South winds 10 to 15 mph.

Tuesday Night: Partly cloudy with a chance of showers and thunderstorms. Lows 57 to 67.

Wednesday and Wednesday Night: Partly cloudy with a chance of showers and thunderstorms. Highs 81 to 91. Lows 57 to 67.

Thursday through Saturday: Clear. Highs 87 to 97. Lows 58 to 68.
Impacts - E19 Information
9.3 FeetMonitor Stage. About 1550 cfs. No flooding in the Mason Valley-Yerington area. Chances of exceeding this flow any year about 1 in 3 per USGS estimate.
9.8 FeetFlood Stage. Minor lowland flooding begins throughout Mason Valley-Yerington area. About 1850 cfs. Chance of exceeding this flow any year about 1 in 4 per USGS estimate.
10.0 FeetMinor flooding of lowlands, pasture, cropland, and some rural roads throughout the Mason Valley-Yerington area. No flooding of structures of roads. About 1950 cfs. Chance of exceeding this flow any year about 1 in 5 per USGS estimate.
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, but little flooding occurs. Some isolated flooding of rural roads. About 2300 cfs. Chance of exceeding this flow any year about 1 in 6 per USGS estimate.
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 little flooding occurs. There may be some minor flooding of yards and basements in Mason. About 2400 cfs, similar to the flood of July 4, 1980.
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 little flooding occurs. Some minor flooding of basements and yards in Mason. About 2500 cfs, like 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. About 2600 cfs, higher than July 1, 2011, but lower than June 19, 1983 floods.
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. About 2700 cfs, similar to floods of July 11, 1995 and June 19, 1983.
11.6 FeetModerate flooding of lowlands throughout the Mason Valley-Yerington area. Structures adjacent to river in floodplain may be damage if not protected. Flooding of many secondary and some primary roads occurs. About 2800 cfs, similar to flood of July 11, 1995.
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. About 3000 cfs; exceeds flood of July 11, 1995, but not as severe as record flood of January 4, 1997.
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. About 3200 cfs.
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. About 3400 cfs.
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.