Crawfish Tales
A Quarterly Publication of the National Weather Service Lower Mississippi River Forecast Center
Slidell, Louisiana


David Reed, Hydrologist In Charge Vol. 8 No. 1, Autumn 2004 Ethan A. Jolly, Editor


Features 2004 Hurricane Season Know Your River Systems:
Red River Basin

From the HIC

With less than a month remaining, the active 2004 hurricane season is about to come to a close. The LMRFC forecast area in western North Carolina and Eastern Tennessee experienced widespread major flooding with two locations recording a flood of record. We provided critical forecasts and services to our customers in this area. Congratulations to the LMRFC staff for a job well done. Our forecasts and activities during this period are documented in this issue.

We have ended the busy fiscal year 2004 and are now in fiscal year 2005. Last fiscal year, we implemented AHPS services at 25 locations in the eastern half of the Tennessee River Valley and completed a significant number of model calibrations to support this implementation. We plan to complete all the necessary calibrations and model development to implement

these services at an additional 27 locations in western Tennessee and northern Mississippi this fiscal year. This development and implementation will take a big part of non-operational time. We will be doing this work along with issuing critical river and flood forecasts and continuing to implement new daily forecast locations and services to meet all customer needs. Again, congratulations to the LMRFC staff for their fine efforts.

We expect a busy year in 2005. We always like to hear from our customers about their needs. Please do not hesitate to call us and let us know how we are doing or if there are other services you will need.

- Dave Reed


Impacts of 2004 Hurricane Season

The relatively dry conditions observed across much of the LMRFC area during the months of July and August changed dramatically in early September with Hurricane Frances which made landfall in Florida on September 5th and traveled up through the southeastern states. Heavy rains fell in the eastern portions of the LMRFC over the southern Appalachian Mountains of Tennessee and North Carolina producing major river flooding. Frances was soon followed by Hurricane Ivan which made landfall on September 16th and Hurricane Jeanne which made landfall on September 25th. Ivan and Jeanne brought additional rainfall to already saturated areas in the mountains of east Tennessee and western North Carolina resulting in significant flooding along the French Broad, Pigeon, and Tuckasegee Rivers and over portions of eastern Tennessee.

Hurricane Frances
Frances spun up rapidly beginning as a tropical depression over the far eastern tropical Atlantic on August 25th and reached hurricane status two days later over the central tropical Atlantic. After moving north of Puerto Rico and across the southern tip of the Bahamas as a category 4 hurricane with winds of 145 mph, Frances weakened to a category 2 hurricane as it crossed over the central and northwestern Bahamas. Frances made landfall on the southeast Florida coast near Seawall’s Point early on the September 5th as a category 2 hurricane. Continuing across central Florida, Frances weakened to a tropical storm then turned northward over the Gulf of Mexico and moved inland over the Florida panhandle.

Figure 1: Storm Total Precipitation 9/4/04-9/9/04
PDA Forecast for New Orleans
Click to go to example page

As Frances continued inland, it produced heavy rainfall across the southeast U.S. The total accumulated rainfall from Frances is shown in Figure 1. The heaviest rains fell over Florida and southern Georgia and over the Appalachian Mountains of North Carolina and South Carolina. Isolated rainfall amounts between 10 and 14 inches occurred over parts of western North Carolina in the LMRFC area. Major flooding, including three modern day records, occurred along the French Broad and Pigeon Rivers. Minor flooding occurred along the Tuckasegee and Nolichucky Rivers. The crest value and type of river flooding observed are shown in Table 1.

Hurricane Ivan
While Hurricane Frances was approaching the Florida coast, Ivan was forming in the eastern tropical Atlantic. Ivan began as a tropical depression on September 2nd and rapidly strengthened into a major hurricane on the September 5th. Moving west-northwest across the central Caribbean, Ivan fluctuated between a category 4 and category 5 storm as it passed just south of Jamaica, over the Grand Cayman Islands, and then into the Yucatan Channel. By September 14th, Ivan was located just north of the Yucatan Channel in the southern Gulf of Mexico as a category 5 hurricane with winds of 160 mph. Initially following a northwestward track across the Gulf, Ivan eventually turned north and then northeast just prior to landfall. As it crossed the Gulf, Ivan slowly weakened, making landfall as a strong category 3 hurricane near Gulf Shores, AL early on September 16th. Ivan continued its northeasterly track inland across Alabama then into eastern Tennessee before continuing northeast toward the Delmarva Peninsula.

Figure 2 : Storm Total Precipitation 9/15/04-9/25/04
PDA Forecast for New Orleans
Click to go to example page

The rainfall associated with Ivan as it moved through the southeastern U.S. is shown in Figure 2. The heaviest rains associated with Ivan were located along the border of Alabama and Florida where 12 to14 inches of rainfall was observed. As Ivan crossed into Tennessee as a tropical depression, it produced 8 to 10 inches of rainfall extending from northern Alabama and Georgia into central Tennessee and another 8 to 12 inches of rainfall along the Appalachian Mountains of North Carolina and South Carolina. The rainfall over the Appalachian mountain region fell in many of the same areas that had already seen significant rainfall from Frances earlier in September resulting in significant flooding along the French Broad River and over parts of east Tennessee. As shown in Table 1, many of the same locations which saw flooding with Frances received additional flooding from the rains from Ivan.

After moving off the east coast of the U.S., the remnant low from Ivan moved southwestward, eventually crossing the Florida peninsula and moving into the Gulf of Mexico. Ivan reformed as a tropical storm and made its second and final landfall in southwestern Louisiana on September 24th. It moved inland into east Texas where it dissipated. Rainfall associated with Ivan’s second landfall was relatively low with only isolated areas in eastern Texas and southwestern Louisiana receiving 3 to 7 inches of rain. No river flooding was observed in the LMRFC area from this rainfall.

Hurricane Jeanne
Jeanne, the final storm of September to affect the LMRFC, began as a tropical depression which formed on September 13th just east of the Leeward Islands. Jeanne strengthened to a tropical storm and moved west-northwestward crossing over the Leeward Islands, Puerto Rico, the Dominican Republic, and Haiti. Jeanne turned northward over the southeastern Bahamas on September 18th and then slowly made a clockwise loop and strengthened to a category 2 hurricane. On September 23rd, Jeanne turned westward. As it crossed the northwestern Bahamas, it strengthened to a category 3 hurricane with winds of 115 mph. It made landfall on September 25th along the east coast of Florida only 20 miles from where Frances had made landfall earlier that month. Jeanne continued across Florida and moved northward into the South and Mid-Atlantic states. The rainfall associated with Jeanne occurred over areas already saturated by rainfall from hurricanes Frances and Ivan. Over the eastern portion of the LMRFC area another 3 to 5 inches of rain fell in the western North Carolina region resulting in isolated areas of minor river flooding.

- Connie Clarstrom

 

Table 1: Flood stages (ft), crest values (ft) and flood categories for LMRFC forecast locations that flooded during hurricanes Frances, Ivan, and Jeanne.
River Location FS Frances Ivan Jeanne
      Crest Category Crest Category Crest Category
French Broad Blantyre 17 25.9 Major* 22.1 Moderate 17.6 Minor
  Asheville 8 14.6 Moderate 11.6 Moderate
  Marshall 8 11.3 Moderate 12.7 Moderate
  Hot Springs 13 18.3 Moderate 22.2 Moderate
  Newport 10 15.0 Minor 17.9 Moderate
Swannanoa Biltmore 12 19.2 Major* 16.7 Moderate
Pigeon Newport 8 18.1 Major 18.9 Major 8.4 Minor
Tuckasegee Bryson City 10 9.95 Minor 13.6 Major
Nolichucky Embreeville 12 14.9 Minor 15.6 Minor
Emory Oakdale 27 30.0 Major
Sequatchie Whitwell 14 16.0 Minor
Chickamauga Chickamauga 18 25.3 Moderate
Paint Rock Woodville 16 17.0 Minor
      * - Modern Day Record        


Know Your River Systems: Red River System

The Red River, one of the longer rivers in the United States, traverses about 1200 miles with its headwaters forming in the Texas Panhandle near the Amarillo area. It flows eastward forming the Oklahoma/Texas border and continues across extreme southwest Arkansas. The River then turns south-southeast and continues in a general southeasterly direction across northwest Louisiana to east central Louisiana and ends above the confluence of the Lower Old River and the Atchafalaya River north of Simmesport, LA. The entire Red River basin has a drainage area of over 91,000 square miles and includes the larger tributaries of the Sulphur River, Cypress Bayou, Bodcau Bayou, Bayou Dorcheat, Black Lake Bayou, and the Ouachita/Black Rivers.

The Red River spans two River Forecast Centers, the Arkansas-Red Basin RFC (ABRFC), and the LMRFC. The ABRFC is responsible for forecasting the Red River at and above Fulton, AR, who then routinely hands off their forecasted flows at Fulton to the LMRFC. The LMRFC takes these flows as input to our hydrologic model to supplement flow forecasting for the remainder of the lower Red River. The LMRFC models the river as two forecast groups: 1) The “Upper Red River” is the drainage from Fulton, AR, downstream to Shreveport, LA; including, the Sulphur River, White Oak Creek, and the Cypress Creeks in northeast Texas and 2) The “Lower Red River” is all drainage below Shreveport; including, the tributaries of Bodcau Bayou, Bayou Dorcheat, Black Lake Bayou, and the Ouachita/Black Rivers. There are five lock and dam structures on the Red River between Shreveport and the Lower Old River making navigation possible from the Atchafalaya River to the Shreveport area. The Old River Locks on the Lower Old River also allows for navigational exchange between the Mississippi River and Red River. During periods of higher flows, it is possible to navigate farther north on the Red River; however, the main channel is generally not maintained north of the Shreveport area.

The Red River’s channel bed below Fulton contains of sand and reddish silt from which the River gets it name. During low flow conditions, large sandbars are visible along the numerous bends of the River. The scenery alternates between remote bottomland woods and an occasional small town. At high stages, normally from December to June, the main channel is continually shifting and changing course, eroding one bank and making deposits on the other. Since the reach of the River between Fulton and Shreveport is densely wooded, fallen trees are frequent and become an obstruction to navigation unless removed. Average annual rainfall over the area ranges from 35 inches over northeast Texas to near 55 inches where the Red flows into the Atchafalaya.

Figure 1
PDA Forecast for New Orleans
Click to enlarge image

UPPER RED RIVER BASIN
River Location Flood Stage Record and Date
North Sulphur Cooper 30 36.16 10/19/1971
South Sulphur Cooper 16 27.21 5/13/1982
Sulphur Talco 20 29.17 12/28/2000
White Oak Creek Talco 16 22.90 3/13/1945
Sulphur Naples 22 37.60 4/1/1945
Black Cypress Bayou Jefferson 13 22.42 4/29/1958
Little Cypress Creek Jefferson 13 22.28 4/26/1966
Big Cypress Creek Jefferson 20 28.78 4/1/1945
Big Cypress Creek Mooringsport 172 182.92 5/5/1958
Red Shreveport 30 45.90 8/10/1849

LOWER RED RIVER BASIN
River Location Flood Stage Record and Date
Bayou Bodcau Bodcau Lake 172 196.67 5/11/1958
Bayou Dorcheat Springhill 11 22.79 4/28/1958
Bayou Dorcheat Dixie Inn 14 25.12 4/8/1997
Bayou Dorcheat Lake Bistineau 142.5 147.79 4/18/1991
Red Coushatta 31 39.90 4/7/1945
Red Grand Ecore 33 44.70 4/10/1945
Red Alexandria 32 45.23 4/17/1945

- Ethan Jolly

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