Rainfall and flooding - Tucson News Now

Rainfall and flooding

STATEWIDE - Learn your vulnerability to flooding by determining the elevation of your property.

Evaluate your insurance coverage; as construction grows around areas, floodplains change. If you are in a flood area, consider what mitigation measure you can do in advance.


Be aware of streams, drainage channels and areas known to flood, so you or your evacuation routes are not cut off.

Avoid driving into water of unknown depth. Moving water can quickly sweep your vehicle away.

Restrict children from playing in flooded areas.

Test drinking water for potability; wells should be pumped out and the water tested before drinking.

Do not use fresh food that has come in contact with floodwaters. Wash canned goods that come in contact with floodwaters with soap and hot water.

Hurricanes are capable of producing copious amounts of rainfall. During landfall, a rainfall amounts of 10 to 15 inches or more is common. If the storm is large and moving slowly, less than 10 mph, the rainfall amounts from a well-organized storm are likely to be even more excessive. This heavy rain usually occurs slightly to the right of the hurricane's track. The amount of rain depends on the size, forward speed and whether the hurricane interacts with other weather systems.

To get a generic estimate of the rainfall amount (in inches) that can be expected, divide 100 by the storm's forward motion, for example, 100/5 mph = 20 inches of rain. For specific rainfall forecasts please monitor local forecasts from the National Weather Service. Rainfall and Flooding fact: Tropical Storm Claudette (1979) brought 45 inches of rain to an area near Alvin, Texas, contributing to more than $600 million in damage.

Inland Flooding From Hurricanes

The next time you hear hurricane -- think inland flooding!

While storm surge has the highest potential to cause hurricane related deaths, more people died from inland flooding associated with tropical systems from 1970 to 1999. Since the 1970's, inland flooding has been responsible for more than half of all deaths associated with tropical cyclones in the United States. Flooding from hurricanes can occur hundreds of miles from the coast placing communities, which would not normally be affected by the strongest hurricane winds, in great danger.

Facts About Inland Flooding From Hurricanes

From 1970 to 1999, 78% of children killed by tropical cyclones drowned in freshwater floods.

One cubic yard of water weighs 1700lbs. The average automobile weighs 3400lbs. Many automobiles will float in just 2 feet of water.

The average person can be swept off their feet in 6 inches of moving water.

The average automobile can be swept off the road in 12 inches of moving water.

At least 23% of U.S. tropical cyclone deaths occur to people who drown in, or attempting to abandon, their cars.

Rainfall is typically heavier with slower moving storms.

Some of the greatest rainfall amounts associated with tropical systems occurs from weaker Tropical Storms that have a slow forward speed (1 to 10mph) or stall over an area. Due to the amount of rainfall a Tropical Storm can produce, they are capable of causing as much damage as a category 2 hurricane.

Source: Federal Emergency Management Agency (FEMA)

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