All flights into Houston’s international airport, one of the busiest in the United States, were halted on Tuesday as Tropical Depression Imelda inundated southeastern Texas with heavy rains and triggered flash flood warnings.

The George Bush Intercontinental Airport tweeted that it was under a “full ground stop” while the National Weather Service said flash flood warnings were in effect for the Houston area through the evening.

The National Hurricane Center forecast that up to 35 inches (89 cm) could fall in some coastal areas, while Energy Texas said over 37,000 people were without power so far. Work at oil refineries southeast of Houston was also slowed or halted.

Houston Mayor Sylvester Turner asked city residents to avoid roads as Imelda’s slow-moving rain bands were expected to hit their peak in the afternoon.

Turner said the city was better prepared to rescue any stranded residents and deal with flooding than when Hurricane Harvey hit in 2017, leading to dozens of deaths in Houston and billions of dollars in damage.

The mayor said that as of mid-morning, a small number of residents had been evacuated because of flooding in northeast Houston.