The Department of Disaster Prevention and Mitigation said summer storms have wreaked havoc to 17 provinces during April 2-6.
Mr Chayapol Thitisak, director-general of the department, said the storms caused damages to 656 homes in 34 districts.
Meanwhile, Bangkok was hit by summer storm last night with heavy rains in many areas until this morning.
Thawi Wattana district was most hit with accumulated rainfall measured at 92 millimetres.
In Lampang, flash flood swept into residential communities in Tambon Bangka of Muang district, causing heavy damages to properties as the muddy water came fast as people were asleep and could not evacuate their properties in time.
Affected villagers said they did not prepare for the forest runoff as it was unusual for the flash flood to occur during this time of the year.
It was the worst flash flood in 10 years, they said.
Source: Thai Public Broadcasting Service (ThaiPBS)