Houston floods signify importance of understanding all flood risk: RMS

The major flooding that took place in Houston this week signifies the need to understand all sources of flood risk.

This is according to Jeff Waters, a meteorologist and manager, model product management at catastrophe modelling firm RMS.

He said:  “Events like these signify the importance of understanding all sources of flood risk—not just coastal and riverine—especially in population centers with significant amounts of exposure.”

The flooding is the latest in a string of such events to impact the southern Gulf states over the last year.

This is the largest flood event Houston has experienced since Tropical Storm Allison in 2001, which recorded more than 35 inches in rain in parts of the area.

According to RMS, this may end up being one of the most severe flood events not caused by a tropical cyclone in Houston’s history.

"Unlike Tropical Storm Allison, which brought prolonged rains over several days, this event was characterised by extremely heavy rainfall over a short period. As a result, the main cause of flooding was pluvial, or surface flooding,” said Waters.

He added: “This type of flooding is common in large urban areas, like Houston, where the majority of surfaces are paved and thus contain minimal water absorption capacity. During high intensity rain events, water quickly accumulates on the surface, often leading to widespread flash flooding.”