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2017 Spring Flood Outlook – early March Update for the Red River and Devils Lake Basins

Prepared by: Gregory J. Gust, Warning Coordination Meteorologist - NWS Grand Forks ND

https://water.weather.gov/ahps2/index.php?wfo=FGF

- Updates - South Basin: Old Snowpack is Gone. - Risk still near Normal! - Spring Snow/Rain. North Basin: Risk slightly lower, but… - High in far North Valley. - Highest in Devils Lake and northeast ND Tribs.






South Basin: Why? Old Snowpack is Gone. - Residual runoff still in river systems. - Heavy Spring Snow or Rain is possible. - Topsoil quite wet/frozen. - Outlook period now extends into early June. - Risk of Thunderstorms is above normal. Flood Risk is near Normal!






North Basin: Why? Sig Snowpack Remains. - Most melt/runoff remains in fields and ditches. - More Spring Snow or Rain is likely. - Deep soil very wet/frozen. - Outlook period now extends into early June. - Risk of Thunderstorms is above normal. Flood Risk is quite High!



2017 Spring Flood Outlook – Early March Update Snow Depth remains high across far north

First, an Overview - Current Conditions. -- Soil Moisture 90-99th percentile - Basis for Concerns. - Flood Risk examples.

Snow Depths have shrunk to half of less of their height, with water content still at 100 to 200+ percent of normal (n-nw).

Trace Amounts


Current Snow Depth ranges from 75 to 200+ percent of normal across the state. 20+ inches central and northern areas.

2017 Snow Depth – Snow Water [previous outlook]

18-28 inches

T to 4 inches

12-24 inches

6-14 inches

16 February 2017 Outlook


2017 Spring Flood Outlook – Early March Update Snow Water remains high across far north

Snow Depths have shrunk to half of less of their height, with water content still at 100 to 200+ percent of normal (n-nw).

Trace Amounts


Red River Basin SWE is highly variable… trace to 4 inches. Devils Lake Basin SWE is generally 3 to 5 inches.

2017 Snow Depth – Snow Water [previous outlook]

16 February 2017 Outlook


2017 Spring Flood Outlook – Early March Update Soil Moisture is still quite high

Image courtesy of NWS/CPC

North: Soil Moisture still 90-99th percentile Northeast ND into far northwest MN.

-- Deep wet soils -- Snow covered South: Soil Moisture now 80-90th percentile in south basin.

-- Bare soil -- Drier deep soil -- Some absorptive capacity.

http://www.cpc.ncep.noaa.gov/soilmst/w.shtml




North: Soil Moisture still 90-99th percentile Northeast ND into far northwest MN. -- Deep wet soils -- Then Snow covered Due to Summer and early Fall Rains especially in North Valley ...since May 1st, 8-14 inches above normal



North: Soil Moisture still 90-99th percentile in DL and north basin. South: Soil Moisture now 80-90th percentile in south basin. Due to late Fall Rains especially in South Valley …since Oct 1st, 1-3 inches above normal


2017 Spring Flood Outlook – Early March Update Precip in February: oil Moisture is still quite high

North: Rain and Snow very near long term normals in Feb. South: Rain and Snow near to slightly below normal… especially in extreme south. Overall new moisture very near normal for February. Somewhat below expected.


2017 Spring Flood Outlook – Early March Update Temps in February: oil Moisture is still quite high

North: Warmer than normal by 3-7 degrees …14th warmest at GF. South: Warmer than normal by 6-10 degrees …6th warmest at FAR. Near-record early thaw process… especially across the south and central Red River Basin.


2017 Spring Flood Outlook – Early March Update Base Streamflow is quite high

-- Soil Moisture 80-99th percentile -- Base Streamflow 90-99th percentile


Freeze-up in late November at near-record flow Eg. Park River at Grafton ND


early February flows measured near-record Eg. Buffalo River at Hawley MN


NWS/NDAWN Frost Depth [Shallow to Normal] As of February 12, 2017

• Varies 8-20 inches across northeast ND and northwest MN.

• Deep/early snow led to shallow frost.

• Record thaws have exposed areas to potential deep frost.

12-20 inches near GFK 20-30 inches near FAR


Outlook issued on 2 Mar 2017 Spring Flood Risk by Category

Moderate Minor

Moderate


Minor to Moderate Flooding Expected Sheyenne River at Valley City

Flood of Record - 20.69 feet 4/13/2009


Minor to Moderate Flooding Expected Red River at Fargo-Moorhead



Moderate plus Flooding Expected Red River at Grand Forks



Moderate plus Flooding Expected Red River at Oslo



Major to Record Flooding Expected Park River at Grafton

Recent Major Floods: 16.16 feet 5/22/2013 ----

16.15 feet 3/29/2004

50% risk of reaching 17.2 feet


Major Flooding Expected Pembina River at Neche



Moderate to Major Flooding Expected Two Rivers River at Hallock



Moderate Flooding Expected Red River at Drayton



Major Flooding Expected Red River at Pembina


50% risk of reaching 50.8 feet


Major Flooding Expected Devils Lake at Creel Bay

2009

- Historical Simulation is what occurred in a particular year. - Conditional Simulation is what those same years could produce given the current basin conditions. Eg. WY 2009 produced 677K acre-ft of inflow, but given the current conditions a 2009-like spring would produce lesser runoff amounts.



- Historical Simulation is what occurred in a particular year. - Conditional Simulation is what those same years could produce given the current basin conditions. Eg. WY 2011 produced 518K acre-ft of inflow, but given the current conditions a 2011-like spring would produce higher runoff amounts.

2009

2011


Major Flooding Still Expected Devils Lake at Creel Bay

Flood of Record: - 1454.30 feet 6/27/2011 Expected Range: 1453.2 - 1454.0

18% risk of exceeding Flood of Record 50% risk of reaching 1453.6 feet



Flood of Record: - 1454.30 feet 6/27/2011


Outlook issued on 2 Mar 2017 Spring Flood Risk by Category

Moderate Minor

Moderate


Issued Thursday morning at 7:09 am CST This Friday Evening’s Weather…

• Lingering cold with Trace snow …will shift to brief thaws early next week.

• Else, wet along the PacNW, w/ increased moist flow into south-

cntrl plains.

Trace snowfall over the Red River and Devils Lake Basins


7-Day Precipitation Forecast March 2-9, 2017

• .10+ inch snowfall on Friday. Trace rain or snow possible next week.

• Strong/wet CONUS systems tracking across NW and south

to OH Valley.


8-14 Day Outlook - updated [mild and wet/snowy]

March 9-15, 2017… Relatively Mild and Snowy or Rainy.


Late Winter- Early Spring Outlook [March - updated]

Now… near to above normal temps. Slight wet signal persists north.


Mid to Late Spring… [Mar-Apr-May]

Trend for near normal Temperatures, with above normal Precipitation





- Updates - South Basin: Old Snowpack is Gone. - Risk still near Normal! - Spring Snow/Rain. North Basin: Risk slightly lower, but… - High in far North Valley. - Highest in Devils Lake and northeast ND Tribs.



Next update… on or around 24 March 2017

Greg Gust - NOAA/NWS Grand Forks ND


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