Freak storms ravaged health facilities in Uttaradit and neighbouring Phrae on Friday, confirming the rainy season is fast approaching, said the Public Health Ministry.
The heavy storm with gusty winds wreaked widespread havoc at Uttaradit Hospital in downtown Muang district, said Public Health Minister Somsak Thepsutin on Saturday.
Windows were shattered in four surgery and internal medical wards. An unspecified number of people were injured by broken glass. Ceilings also partially caved in at a laboratory.
Mr Somsak said the structural damage has been assessed. Repairs to the buildings were underway and expected to be finished in a week.
"The situation has returned to normal. Soldiers and officials from the Interior Ministry were sent to deliver an emergency response which was completed within two hours of arrival at the scene," he said.
The hospital's operation was not disrupted by the storm.
Mr Somsak on Saturday said he instructed hospitals and medical facilities in provinces where storms were forecast to stay alert.
They were instructed to reinforce the strength of windows and doors and coordinate with the military, the Interior Ministry and the Provincial Electricity Authority to have their officials on standby in case immediate assistance is required in the event a storm hits.
In Phrae, the roof of the provincial public health office was leaking rainwater as the storm damaged the control and dentistry rooms.
The force of the wind also peeled off the roof of a nearby Thai traditional medicine station. In Song district, Song Hospital was surveying the damage from the storm and was devising a repair plan.
As a result of the storms which swept through the northeastern provinces on Friday, three workers were killed in Bung Kan and one person died in Khon Kaen.
In Bung Kan, three workers at a construction site of the Friendship 5 project connecting Bung Kan with Laos were crushed by a crane which tipped over during the heavy storm.
The workers had taken shelter from the storm near the crane when it fell over and crushed them in strong winds and lashing rain. Rescuers spent more than an hour extracting the bodies from underneath the crane.
In Nong Bua Lam Phu, a hailstorm uprooted trees, blew off the roofs of many homes and caused widespread blackouts in four districts where damage was reportedly caused to at least 750 homes.
The storm knocked down a wall which came down on a resident who died instantly in Khon Kaen.
Elsewhere in the province, powerlines were down and tap water stopped running for hours as the water production station was crippled by heavy rain.
The Office of the National Water Resources, meanwhile, has predicted the intense heat and summer storms will prevail over the upper North and upper Northeast from now until May 9.
The weather bureau has forecast the rainy season will start from the third or fourth week of this month.