Cynthia Palmer Science and Operations Officer National Weather Service – Shreveport Special Thanks to Craig S. Ross, Tony Hurt, & Julianna Glinskas
Overview Two periods of flooding along the Red River Late Spring – Early Summer (May 10 th – July 5 th ) Late Fall – Early Winter (November 26 th – January 7 th ) Rainfall Placement: North Central Texas and South Central Oklahoma (May/Jun) Northeast Texas and Southeast or East Oklahoma (Nov/Dec) Quantity Percent of Normal: 150-600%
Red River Basin
May Rainfall Totals Record Rainfall: • Widespread 10+ inches over the Red River basin. • Broad area of 20+ inches upstream of Lake Texoma and Hugo Lake. • Percent of Normal: 200-600% • Wettest May on record for TX and OK. Hugo Lake Denison Dam Pecan Point
June Rainfall Totals Hugo Lake Denison Dam Pecan Point Percent of Normal: 150-600% upstream of Denison Dam
Lake Texoma Lake Texoma Stats: • Well below the conservation pool until the end of April. • Look at how quickly the reservoir filled. • Crested the dam’s spillway (640 ft.) twice this spring/summer. • May 24 th • June 18 th • Broke its record highest elevation with 645.72 ft. on May 29 th . Courtesy of USACE
Discharge from Lake Texoma and Hugo Lake Courtesy of Tony Hurt
Hydrograph for Pecan Point near DeKalb, TX – Spring/Summer Flood Major Flood Stage Moderate Flood Stage River Stage in Feet Minor Flood Stage Action Stage First Forecast within 6 inches of observed crest First Forecast within 6 June 19 – 25.7 ft. inches of observed crest Forecast 33 ft. May 27 – 33.5 ft. Forecast 34.5 ft. Observed Crest June 25 – 32.44 ft. {6 days} Observed Crest June 2 – 35 ft. First Flood Warning {7 days} Issued May 8 – 11.42 ft. Date
Thanks to TXKToday.com
Hydrograph for Index, AR – Spring/Summer Flood
Hydrograph for Fulton, AR – Spring/Summer Flood
Arkansas Flood Pictures – Red Still Rising on May 31 st Fulton, AR Hwy 71,AR
Hydrograph for Shreveport, LA – Spring/Summer Flood
Flooding in Shreveport/Bossier City
Flooding in Shreveport/Bossier City
How has the Red River changed in Downtown Shreveport since 1990?
Hydrograph for Coushatta, LA – Spring/Summer Flood
Bayou Pierre/Coushatta Flooding
Hydrograph for Grand Ecore, LA – Spring/Summer Flood
Flood Fight in Natchitoches
Spring/Summer Flood Summary Rain fell nearly all up stream of Lake Texoma and Lake Hugo. Dension Dam spilled over the uncontrolled spillway twice Prolonged crest ranged between 48 and 72 hours at all gauges . Pecan Point stayed above flood stage for 55 days (May 10 th – July 4 th ). Grand Ecore stayed above flood stage for 50 days (May 18 th – July 6 th ).
How does this Spring/Summer Flood Compare to Past Floods? First major flood along the Red River since 1990. First major flood since the Red River Waterway was completed. Second worst flood at Grand Ecore. Third worst flood: At Pecan Point, and nearly eclipsed the May 1908 Flood, cresting at 35 ft on June 2 nd . At Index. At Coushatta. Ranked 18 th for Fulton. Ranked 25 th for Shreveport. Worst flood in 70 years.
Impacts – Late Spring/Early Summer Thousands of acres of pasture and farm land were flooded. Hundreds of livestock had to be evacuated. Bank erosion was extreme. The US Highway 259 , Highway 8, and Highway 71 bridges were closed over the Red River, and Highway 37 bridge over the Red River was threatened. A number of structures and homes suffered damage. Several county roads, culverts, and bridges needed repair. $74,000,000 reported in damages to the NWS. Estimated over $100,000,000 total.
November Rainfall Totals Hugo Lake Denison Dam Pecan Point Percent of Normal: 200-400%
December Rainfall Totals Hugo Lake Denison Dam Pecan Point Percent of Normal: 150-600%
Hydrograph for Pecan Point near DeKalb, TX – Fall/Winter Flood
Hydrograph for Shreveport, LA – Fall/Winter Flood
Hydrograph for Shreveport, LA – Fall/Winter Flood
Hydrograph for Coushatta, LA – Fall/Winter Flood
Hydrograph for Grand Ecore, LA – Fall/Winter Flood
Fall/Winter Flood Summary Rain fell further east, with more breaks between systems. Rain fell in the uncontrolled sections and tributaries of the Red River. Comprised of 3 separate crests for Pecan Point. Nov 26 th – Dec 3 rd (Tied for the 9 th worst flood) Dec 16 th – Dec 18 th Dec 25 th – Jan 6 th (Tied for the 9 th worst flood) Not all points along the Red River reached flood stage. Impacts: Record Pool Stage on Broken Bow Lake (629.47 ft on December 28 th ). Thousands of acres of pasture and farm land were flooded. Livestock had to be evacuated.
Rainfall Comparison Summary • Widespread 15 to 20+ inches fell May Rainfall upstream of Lake Texoma and Lake Hugo. (Percent of normal: 300-600+) • Widespread 10 to 15 inches fell Hugo Lake mainly downstream of Lake Denison Dam Texoma and Lake Hugo. (Percent Pecan Point of normal: 200-400+) November Rainfall Rainfall axis shifted east Hugo Lake during the fall Denison Dam Pecan Point and winter.
El Nino Winter Climatology & Current Anomaly by Region Typical January through March Weather Anomalies and Atmospheric Circulations during a Moderate to Strong El Nino.
Sea Surface Temperatures Anomalies • Strong El Nino conditions continue across the Equatorial Pacific. • November to January ONI (2.3) ties 1997/98 for the largest November to January value, and likely the peak of this El Nino. • El Nino should gradually weaken through the spring, transitioning to ENSO neutral during the late spring and early summer.
Rainfall Anomalies Since October 1, 2015 Since January 1, 2016
Shreveport Monthly Normals (1981- 2010) Shreveport 2015: 65.26 inches (51.41 inches normal)
Outlooks for March – May
Outlooks for April – June
Lower Red River Basin – Where are we right now? Flood Control Pools Conservation Pools
Where are we now?
What does this mean for our upcoming spring and summer? The Red is still running on the high, because of reservoir releases at Lake of the Pines and Lake Wright Patman. Rainfall could cause additional flooding along the Red River through the spring. Tropical systems this summer could also cause additional flooding. Prepare for high water to continue.
Recommend
More recommend
