AUGUST MONTHLY HAZARD: DROUGHT
Drought can sneak up on a region over time (compared to flooding) but can be aggravated by high temperatures, high winds, and low relative humidity. The multiple factors related to drought make it hard to give accurate, reliable, and timely estimates of drought severity and effects. Looking at past records, Tulsa experiences a drought about every 5 years. It has less drought than most parts of Oklahoma.
There are 4 stages of drought: meteorological (less precipitation than the average), agricultural (not enough precipitation for vegetation and crops), hydrological (drop in water levels, such as groundwater and streams), and socioeconomic (when water is scarce enough to cause social or economic hardship).
The main impact of drought in Tulsa is economic, as crops are lost due to lack of precipitation. In severe drought, there is a risk of fire, as vegetation becomes easily flammable. Tulsa has prepared for the event of drought by getting water for the city from different watersheds. Even still, rationing may also be put into effect, as needed.
The main danger to buildings/city infrastructure is drought’s effect on expansive (shrinking/swelling) soils. For example, a combination of extreme heat and soil movement caused above average numbers of water line breaks in Tulsa during the summers of 2011 and 2012.
For more information on drought visit the USDA Drought site at https://www.usda.gov/topics/disaster/drought. You might also want to check our August Key Message on low impact development (LID), which includes techniques that can be used as tools in water conservation: http://disasterresiliencenetwork.org/august-key-message-low-impact-development/.