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 NevadaRiver Group: Eastern Sierra
Issuance Time: May 25 2019 at 9:07 AM PDTNext Issuance: May 26 2019 at 9:00 AM PDT
Monitor Stage: 9.0 FeetFlood Stage: 9.8 Feet

SPECIAL 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.

Verification - Historical Graphical RVF
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Historical Stage/Flow Data
Water Year
Peak Discharge (cfs)
Stage (feet)
Date
 Most Recent 5 Years
2017
2,910
10.94
Jun 24, 2017
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
 Historical High Stage/Flow Events (Period of Record - April 1974 to Present)*
1997
3,900**
12.72
Jan 04, 1997
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
 * 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: Chance of showers in the morning, then showers and slight chance of thunderstorms in the afternoon. Snow level 7500 feet. Snow accumulation up to 2 inches. Highs 50 to 60. Southwest winds 10 to 15 mph. Gusts up to 30 mph in the afternoon.

Tonight: Showers and slight chance of thunderstorms in the evening, then chance of showers after midnight. Snow level 6500 to 7000 feet. Snow accumulation up to 3 inches. Lows 35 to 45. West winds 10 to 15 mph. Gusts up to 30 mph in the evening.

Memorial Day: Mostly cloudy. Chance of showers in the morning, then chance of showers and thunderstorms in the afternoon. Snow level rising above 8000 feet. Highs 56 to 66. West winds 10 to 15 mph. Gusts up to 30 mph in the afternoon.

Monday Night: Mostly cloudy. Chance of showers and thunderstorms in the evening, then slight chance of showers after midnight. Lows 40 to 50. West winds 10 to 20 mph. Gusts up to 35 mph in the evening.

Tuesday: Mostly cloudy with a slight chance of showers. Highs 60 to 70. Northwest winds 10 to 15 mph.

Tuesday Night: Partly cloudy. Slight chance of showers and thunderstorms in the evening. Lows 41 to 51.

Wednesday: Partly cloudy. Chance of showers and thunderstorms in the afternoon. Highs 64 to 74.

Wednesday Night: Mostly cloudy. Chance of showers and thunderstorms in the evening. Lows 43 to 53.

Thursday and Thursday Night: Partly cloudy with a chance of showers and thunderstorms. Highs 66 to 76. Lows 45 to 55.

Friday: Partly cloudy. Chance of showers in the afternoon. Highs 67 to 77.

Friday Night: Mostly cloudy with a chance of showers in the evening, then partly cloudy after midnight. Lows 44 to 54.

Saturday: Partly cloudy. Chance of showers and thunderstorms in the afternoon. Highs 70 to 80.
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.
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.