National Weather Service Weather Forecast Office

Flooding is America’s number one disaster, on average, costing billions of dollars and hundreds of lives annually. Nearly all cities and many towns have experienced flooding at one time or another. In 2012, despite another very dry year for many across the Rio Grande Valley, there were two notable flood events. On March 29th, the devastating McAllen hailstorm also dropped four to six inches of rain which flooded much of the city. The floods submerged more than 100 vehicles and pushed the city’s intricate drainage and pumping system to 90 percent of capacity. On June 30th, nearly six inches of rain fell on Brownsville and flooded some areas with more than 2 feet of standing water. Heavy rainfall the same day pushed fast flowing water across Highway 83 near Roma. On July 13th, an estimated six inches fell on central Jim Hogg County ranches.

After a top five driest 2011 across the Rio Grande Valley and an all time driest 2011 in Texas, which correlated to zero flood fatalities in the state, occasional bouts of torrential rainfall in central, north, and east Texas contributed to five fatalities in 2012 – the highest for any state.

Rio Grande Valley residents should never let their flood guard down. It only seems like yesterday when flooding was a primary story in 2010, starting with a week long period of locally heavy rainfall April 12th through 18th that produced localized floods in Brownsville, McAllen, Mission, and Harlingen. Flooding affected the May 18th morning commute around McAllen, and persistent thunderstorms flooded Falfurrias on May 25th. These events were just a prelude to the big flood story of 2010, led off by Alex on June 30th and July 1st, and culminating with the Rio Grande Flood through July and August. Finally, the flood season finished in style, as mid September heavy rainfall flooded Cameron County.

In 2008, the Rio Grande Valley was no stranger to flooding, either. Hurricane Dolly dropped more than a foot of rain on portions of Cameron and Willacy Counties during late July; another foot of rain fell in and near Roma (Starr County) between August 18th and 25th. In each case, hundreds, if not thousands, of structures were flooded, and water rescues of stranded residents were necessary. Click here for a short video of freshwater flooding in northeast Cameron County due to Hurricane Dolly.

How will the rest of 2013 fare? Trends and teleconnections (i.e. El Niño/Southern Oscillation, Arctic/North Atlantic Oscillation, etc.) suggest that spring into early summer 2013 will resemble the warm and very dry spring of 2011. While it is to soon to forecast individual late and summer rain events, we must remember the Rio Grande Valley is in a river delta. The low lying landscape, combined with plenty of poor drainage areas, means that heavy rain in a short period of time can cause big problems – any time of year.

Flooding and Fatalities
Flooding remains the number one cause of weather related fatalities in Texas over the long term. Texas leads the nation in the number of flood related deaths in the past 50 years. Pennsylvania rates a distant second, with about 3 times fewer flood related deaths. Some of the high flood mortality rate can be explained by the sheer size of Texas, combined with its unique location in the center of frequent air mass "wars" between warm, humid air from the Gulf of Mexico and Bay of Campeche with drier, cooler air masses moving off of the southern Rockies and northern Sierra Madre in Mexico. However, human behavioral issues may also contribute to the value. Click here for more details on Texas Flood Fatalities.

National flood deaths fell to their lowest level (23 stateside, 5 Puerto Rico) in more than fifty years (prior to 1960, National Climatic Data Center). Reasons for the dearth of death include the extensive 2012 heat and drought. Nearly every state ranked among the top ten warmest since 1895; more than half the states had below normal, much below normal, or record driest conditions while only six states had above normal or much above normal precipitation. Hurricane Isaac (late August) and Superstorm Sandy (late October) were remarkable for storm surge flooding but, unlike Hurricane Irene in 2011, were unremarkable for rain–induced flooding.

The following statistics were compiled for events recorded in Storm Data for direct flood related deaths, nationwide (including Puerto Rico), in 2012:

Stay safe this year! The following information, and links, can help you prepare for flooding - anytime, and anywhere.