Parts of southern and eastern Spain were hit by severe flash flooding on Tuesday, as some locations received up to 12 inches of rain in just a few hours.

Footage from the city of Valencia showed mud-colored water flooding through the streets, tearing down walls, and sweeping away parked cars.

Spanish Prime Minister Pedro Sánchez said an unspecified number of people are missing due to the flooding, and asked citizens to act with “great caution” and avoid moving around if it is not necessary.

Extreme rain warnings were in effect on Tuesday for some areas including around Valencia, according to Spain’s Meteorological Agency, AEMET. These warnings called for the potential of 200 mm (4 inches) of rain in less than 12 hours.

In some locations, the rainfall estimates were exceeded in even shorter periods of time. Chiva, which is east of Valencia, received 320 mm of rain in just over four hours

The Valencia area averages 77 mm (3.03 inches) for the entire month of October.

Flooding was also reported in and around Murcia and Malaga with over 100 mm (4 inches) of rain falling in some of these areas.

A strong upper level low pressure is moving northward into the region from Africa.  The strong system is bringing a significant amount of atmospheric instability to the region.  Extreme amounts of rainfall are also being enhanced with moisture from the Mediterranean Sea and upslope flow into higher terrain which acts to squeeze out additional moisture.

Rainfall warnings continue through Wednesday for portions of eastern and southern Spain, according to AEMET. The warnings north of Valencia are for rainfall totals in excess of 100 mm (4 inches) and rainfall rates of 30 mm per hour (1.18 inches per hour).

Areas of southwestern Spain will see the threat of heavy rain continue through the end of the week