The National Weather Service released its assessment of the May flood Wednesday and identified a number of key findings and recommendations for improved service to the Nashville area.
Related: Click here to read the full report.
The report found that the National Weather Service and the Army Corps of Engineers did not communicate effectively during the flood about how much water was being released through the Old Hickory Dam.
Since the NWS didn't get accurate information from the Corps about how much water was being dumped into the Cumberland River, it meant the NWS's flood predictions were off and lagged behind what was actually happening.
Also, the NWS said people did not respond and evacuate quickly because many people simply didn't understand their flood warnings.
The Channel 4 I-Team was the first to report the communication problems. I-Team Chief Investigative Reporter Jeremy Finley learned that when workers at NWS called the Corps the night before the worst of the flooding, no one picked up the phone because the downtown staff had been sent home.
The lack of accurate information led to inaccurate river crest forecasts along the Cumberland River. Many Nashville residents told investigators that they had no warning, despite several watches and warnings from the local Weather Forecast Office.
The Cumberland River rose more than 33 feet, cresting at 51.86 feet on Monday, May 3. That was about 10 feet higher than the original forecast issued Sunday morning.
Twenty-six people died due to flood-related incidents, 11 in Davidson County. Nashville suffered more than $2 billion in flood damage.
The NWS said it is unclear if the fatalities were a result of the locations of the flooding or a lack of forecast understanding, especially from the senior citizens who died.
The NWS said it will begin to introduce spring weather maps that will show if there is flooding and how it will impact neighborhoods.
"The National Weather Service report confirms the breakdown in communication during the historic flooding last year. We can't stop the rain, but we can and must do a better job at warning people of the potential for dangerous flooding. A few hours of warning could have saved lives and prevented millions of dollars in damage," said U.S. Rep. Jim Cooper in a news release.
U.S. Sen. Lamar Alexander called the NWS's new flood-prediction efforts "an important step" toward making the agency's flood warnings more like its tornado predictions.