The death toll was on the verge of topping 100.
In some places, only the roofs of homes could be seen. International aid is on the way following appeals by the government, but so far, most of the help has come from volunteers ferrying noodles, rice and clean water door-to-door in small boats.
Heavy monsoon rains that began in late June compounded more recently by Cyclone Komen have triggered some of Myanmar's worst flash floods and landslides in recent memory.
The death toll reached 99 today and more than 900,000 people have been affected, a third of them in the Irrawaddy Delta, said Phyu Lei Lei Tun, director of the Ministry of Social Welfare, Relief and Resettlement.
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It is here in a desperately poor region known as the Rice Bowl, that several mighty rivers meet before feeding into the sea.
Downstream waters have caused banks to burst, swallowing up rice paddies and homes.
Zin Mar Htun was seeking refuge in a school with six family members, including her 11-month-old son, after their house was flushed away in the raging waters. "We had our own raft, so we sought refuge here," she said.
Myanmar's appeal was in sharp contrast to its response following Cyclone Nargis in 2008, when the nation's then-military rulers refused international aid and largely downplayed the destruction - though more than 100,000 people were killed.
A nominally civilian government now runs the country, but critics say it's not moving quickly enough to help those in need.