National Weather Service United States Department of Commerce

APPENDIX A

Time Table: Flood of 1997 at East Grand Forks, Minnesota

 

Date(s) Time (local) Comments
2/6 - 9/97 Airborne snow survey of the Red River of the North conducted.
2/13/97 First Snowmelt Outlook issued using data from the airborne snow survey. The potential for spring flooding was characterized as "Severe" defined as levels at or exceeding the previous flood of record.
2/19 - 23/97 Airborne snow survey of the Red River of the North conducted.
2/20/97 USACE requested internal numerical flood crests. Decision to issue second Snowmelt Outlook in a numerical rather than categorical fashion was made and coordinated by the NWS.
2/24/97 Emergency managers notified that updated Snowmelt Outlook on 2/27/97 would be numerical.
2/27/97 Snowmelt Outlook updated. Outlook called for 47.5 feet with no additional precipitation and 49.0 feet with normal additional precipitation. The 49.0-foot forecast exceeded the existing flood of record that occurred on 4/26/79 (48.8 feet). Record numerical peak forecasts allowed the USACE to initiate advanced flood protection measures earlier than would otherwise have been possible.
3/6 - 12/97 Airborne snow survey of the Red River of the North conducted.
3/13/97 Snowmelt Outlook updated. No change from guidance issued on 2/27/97.
3/18 - 21/97 Airborne snow survey of the Red River of the North conducted.
3/23 - 27/97 Airborne snow survey of the Red River of the North conducted.
3/27/97 Snowmelt Outlook updated. No change from guidance issued on 3/13/97.
3/30/97 Flood Warning issued for all NWS river forecast points in the Red River of the North Basin.
4/3/97 1220 Current stage 18.1 feet. Forecast to continue to rise. Outlook with normal pcpn 49.0 feet.
(Note that river model indicates that forecast peak may be well below the outlook peak of 49.0 feet, but forecasters were reluctant to lower the guidance.)
4/4/97  1230 Current stage 23.6 feet. Forecast to rise to FS by 4/5. Outlook crest with normal pcpn 49.0 feet.
4/5 - 6/97 Severe blizzard conditions throughout Red River of the North. One to three inches of precipitation falls. Cold, windy, and snowy conditions hampered data collection and flood-fight activities.
4/5/97 1500 Current stage 28.4 feet. Outlook crest with normal pcpn 49.0 feet.
4/6/97 1330 Current stage estimated at 35.7 feet. Outlook crest 49.0 feet.
(Note that since above normal precipitation had already occurred, the condition for the outlook crest was dropped.)
4/7/97 1400 Current stage 36.5 feet. Outlook crest 49.0 feet in mid- to late April.
4/8/97  1630 Current stage 38.8 feet. Outlook crest 49.0 feet in mid- to late April.
4/9/97 1210 Current stage 41.5 feet. Outlook crest 49.0 feet in mid- to late April.
4/9 - 12/97 Airborne snow survey of the Red River of the North conducted.
4/10/97  1300 Current stage 41.6 feet. Outlook crest 49.0 feet in mid- to late April
4/11/97  1230 Current stage 42.0 feet. Outlook crest 49.0 feet beginning 4th week of April.
4/12/97 1130 Current stage 42.3 feet. Outlook crest 49.0 feet beginning 4th week of April.
(USGS measurements of flow indicate that ice effects are causing a 3.55-foot shift above the current rating curve).
(Airborne snow survey completed.)
4/13/97  1110 Current stage 42.8 feet. Outlook crest 49.0 feet. This crest will be very broad, occurring as early as April 19, and extending as late as April 21-22.
(Updated estimates of areal snow water equivalent delivered to the NCRFC for use in runoff model.)
4/14/97  1630 Current stage 43.7 feet. Crest 50.0 feet - April 19-22.
(Note this is the first non-outlook crest forecast for East Grand Forks).
4/14 - 17/97 Airborne snow survey of the Red River of the North conducted.
4/15/97  1330 Current stage 45.3 feet. Crest 50.0 feet - April 22-23.
4/15/97  2134 Current stage 46.4 feet. Crest 50.0 feet - April 22-23.
(USGS measurements of flow indicate ice effects are causing a 1.44-foot shift above the current rating curve).
4/16/97 0950 Current stage 47.5 feet. Rise to 49.0 to 49.5 feet - April 17, then slow rise to 50.0 feet April 22-23.
(USACE field construction personnel alerted to raise emergency flood protection by raising top of the levee to a stage of 54.0 feet.)
4/16/97 1620 1600 stage 48.4 feet. Rise to 49.5 feet by early April 17, then continue rise to crest of 50.0 to 50.5 feet - April 20-22.
4/16/97  2120 Current stage 48.8 feet. Rise to near 49.5 feet early on April 17, then continue rise to crest of 50.0 to 50.5 feet - April 20-22.
(USGS measurements of flow indicate a 0.94-foot shift above the current rating curve).
4/17/97  1215 Current stage 49.6 feet. Crest 50.0 to 50.5 feet April 18 p.m. - April 19 a.m.
(USACE contracts for additional resources to raise levees).
4/17/97  2125 Current stage 50.9 feet. Crest 51.5 - 52.0 feet - April 18; April 19. Ice effects in the area appear to be causing fluctuations in the rate of rise.
4/18/97 0905 Current stage 52.0 feet. Crest 53.0 ft April 18-19.
(Severe seepage and boils behind levees in Belmont Park, Lincoln Park, and Central Park areas of Grand Forks with similar problems in East Grand Forks.)
(Severe seepage and boils behind levees in Belmont Park, Lincoln Park, and Central Park areas of Grand Forks with similar problems in East Grand Forks.)
(Sandbag levee on the Point in East Grand Forks breached allowing inundation of the Point area, following failure of efforts to shore up the levee.)
(Numerous levee failures occurred on both sides of the river. USACE reported that all levee breeches and over-toppings appear to have occurred between river stages of 51.6 and 53.0 feet.)
4/18/97 1950 1900 stage 52.6 feet. Crest near 54.0 feet late Saturday (April 19).
4/19/97  0945 0500 stage 52.9 feet. Little change next few days - additional rises of 0.2 to 0.3 foot are possible.
(Fire broke out in Grand Forks and destroyed 11 buildings).
4/19/97 1510 1200 stage 53.1 feet. Rise to near 54.0 feet over the next few days.
4/19/97  2010 1800 stage 53.3 feet. Slow rise to near 54.0 feet next few days.
4/20/97  1135 Current stage 53.7 feet. Crest 54.0 ft - April 21. Fluctuations of 0.1 to 0.3 feet are possible.
(Hydrologic Service Area (HSA) responsibility transferred from NWSO FGF to NWSFO BIS)
4/20/97 2106 Current stage 53.9 feet. Crest 54.0 feet - 4/21. Fluctuations of 0.1 to 0.3 ft are possible.
4/21/97  1235 Current stage 53.9 feet. Near crest; remain near this level for several days. Fluctuations of 0.1 to 0.3 foot are possible.
4/21/97  2130 Estimated stage 54.0 feet. Near crest; remain near this level for several days.
4/22/97  1130 Estimated stage 54.0 feet. Cresting; little change next 24-48 hours.
4/22/97  2119 Current stage 53.8 feet. Cresting; little change next 24-48 hours.
4/23/97  1010 Current stage 53.6 feet. Continue very slow fall next several days.
4/23/97 2116 1600 stage 53.2 feet. Continue very slow fall next several days.
4/24/97  1000 Current stage 52.6 feet. Fall to 51.0 feet by late April 25. Fall to 50.0 feet by 4.27. 0.1 to 0.3 foot surges in stage are possible.
4/24/97  2118 Estimated stage 52.0 feet. Fall to 51.0 feet by late April 25. Fall to 50.0 feet by 4.27. 0.1 to 0.3 foot surges in stage are possible.
4/25/97  1045 Stage missing. Slow fall.
4/25/97  2124 Current stage 50.5 feet. Continue slow fall.
4/26/97  . 0945 Current stage 49.7 feet. 3-day forecast: 48.0/46.8/45.9 feet
4/26/97  2124 Current stage 49.1 feet. 3-day forecast: 48.3/47.2/46.3 feet.
4/27/97  0935 Current stage 48.2 feet. 3-day forecast: 47.0/45.8/44.3 feet.
4/27/97  2142 Current stage 47.6 feet. 3-day forecast: 47.1/46.0/45.3 feet.
4/28/97  0935 Current stage 46.9 feet. 3-day forecast: 46.0/44.6/43.2 feet.
4/28/97  2118 Current stage 46.4 feet. 3-day forecast: 46.0/44.6/43.2 feet.
4/29/97  1045 Estimated stage 46.2 feet. 3-day forecast: 45.5/44.8/44.4 feet.
4/29/97  2119 Current stage 45.3 feet. 3-day forecast: 45.0/44.5/44.1 feet.
4/30/97  0915 Current stage 44.8 feet. 3-day forecast: 43.9/42.7/41.5 feet.
5/01/97 1005 Estimated stage 43.9 feet. 3-day forecast: 43.0/42.1/41.2 feet.
5/02/97  1025 Current stage 43.8 feet. 3-day forecast: 43.0/42.2/41.4 feet. Continued slow fall
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