Severe Weather Toolkit

1.4 Flooding

Texas regularly leads the nation in flood fatalities and property damage. The geography of the area makes it uniquely positioned to take both the brunt of tropical hurricanes and large air masses that bring in moisture from almost any direction. Texas holds at least one-half of the 12 world records for rainfall in 48 hours or less. Schools should consider flooding in planning for severe weather emergencies. (FloodSafety.com: USGX Flood Histories).

Rainfall associated with severe thunderstorms can have an extreme effect on school operations, especially transportation. When planning for potential flooding, the National Weather Service (NWS) is one of the best resources for guidance. Monitoring weather conditions from both local sources and the NWS is an important part of emergency operations. The NWS River Forecast Centers routinely issue Flash Flood Guidance throughout the day for every county in the area. Local and County Emergency Managers are a good resource for collaborative flood planning and response guidance.

NWS Flooding Conditions Definitions

Flash Flood

A flood which is caused by heavy or excessive rainfall in a short period of time, generally less than six hours. Also, a dam failure can cause a flash flood, depending on the type of dam and time period during which the break occurs.

Flash Flood Watch

A flash flood watch is issued to indicate current or developing hydrologic conditions that are favorable for flash flooding in and close to the watch area, but the occurrence is neither certain or imminent.

Flash Flood Warning

A flash flood warning is issued to inform the public, emergency management and other cooperating agencies that flash flooding is in progress, imminent or highly likely.

Flash Flood Statement

A statement by the NWS which provides follow-up information on flash flood watches and warnings.

Urban and Small Stream Flooding

Flooding of small streams, streets, and low-lying areas, such as railroad underpasses and urban storm drains. This type of flooding is mainly an inconvenience and is generally not life threatening nor is it significantly damaging to property.

Urban and Small Stream Flood Advisory

An urban and small stream flood advisory alerts the public to flooding which is generally only an inconvenience (not life-threatening) to those living in the affected area. This advisory is issued when heavy rain will cause flooding of streets and low-lying places in urban areas. Also used if small rural or urban streams are expected to reach or exceed bank full. Some damage to homes or roads could occur.

Reviewing Faility Flood Plains

It is essential to complete a detailed review of all district facilities in relation to flood plains. Likewise, areas that experience drainage and run off issues associated with high rainfall amounts should be reviewed even if they are not located in a flood plain. This will allow the district or campus to design specific protective actions during flooding. Unlike tornado response, it may be necessary to move to a higher floor in the event of rising water.

Considerations When Flash Flooding or Rising Water is Expected

  • Monitor weather watches and warnings
  • Maintain contact with local law enforcement and other agencies for road conditions and guidance for protective actions and evacuation
  • Have transportation department personnel and drivers on standby for evacuation
  • Remind staff of protective actions outlined in the school's EOP
  • Move students and staff from portables or temporary structures
  • Disconnect electrical appliances
  • Make certain to locate utility shut-offs and have staff available and ready to shut them down as needed
  • Provide appropriate communication to staff, students, parents and the community
  • Prepare for possible evacuation. Take go kits, attendance roster, and other supplies.
  • Ensure that evacuation sites are ready and available if needed
  • If evacuating, send appropriate staff to receiving facility in advance of evacuation
  • Take mitigation actions to minimize flooding potential in areas of the facility that might take on water. (Examples: Securing doors, placing sand bags or other barriers)
  • Locate a bottled water supply. Discontinue use of water from faucets if advised
  • Anything left on the floor may be destroyed by floodwaters. Move important items such as computers, electronics, and teaching materials off the floor. (Example: Consider relocating computer hard-drives off of the floor and on to the tops of desks.)

Transportation Considerations During Flooding

There are many transportation challenges associated with flooding and evacuations. Drivers must have training based on district protective actions and protocol. While buses have a high clearance and could drive through shallow standing water, they still can be swept away by moving or rushing water. Drivers should not drive into moving or high water. "TURN AROUND DON'T DROWN is a national campaign designed to alert the public not to drive or walk across a flooded roadway. If it is unsafe to continue, drivers should seek a safe area on high ground. Be aware of crumbling roadways and wash out areas that could trap the bus

Flooding Resources

Flood Watch and Warning Checklists

References

National Weather Service http://www.weather.gov/bgm/severedefinitions