For a simple yet very avoidable reason, reports the Charlotte Observer:

The 13 North Carolina deaths attributed so far to Hurricane Matthew follow a familiar pattern: drivers’ fatal challenges of water-covered roads and bridges.

Flooding killed an average of 84 Americans a year between 2006 and 2015, the National Oceanic and Atmospheric Administration says. About half of them – the Weather Channel says nearly two-thirds between 1995 and 2010 – died in their vehicles.

Most made the worst possible decision: driving into water of unknown depth.

Nine or 10 of the 13 confirmed deaths in North Carolina from Hurricane Matthew fall into that category. And it doesn’t take much fast-moving water to create a dangerous situation:

Six inches of fast-moving floodwater can knock over an adult, NOAA says. Twelve inches of rushing water can carry away a small car.