While countries are managing to control the disaster death toll, economic costs are increasing more than ever before, said Margareta Wahlstrom, the UN special envoy on disaster risk reduction.
She called the $380 billion figure "the minimum" cost, two thirds higher than the last record in 2005 when the United States suffered huge losses from Hurricane Katrina.
This time, earthquakes in Japan and New Zealand, as well as floods in Thailand and other countries sent the cost skyrocketing. "Earthquakes are the costliest and the deadliest of disasters," Wahlstrom told a press conference to mark the first anniversary of the Japan quake on March 11 last year.
The quake, tsunami and nuclear explosion at Fukushima caused more than $210 billion of damage, according to the UN disaster risk reduction agency headed by Walhstrom.
It has put the cost of the Thailand floods at more than $40 billion.
New Zealand's central bank has estimated that the deadly earthquake on February 22 last year caused about $25 billion in losses, just for rebuilding.
"The main message is that this is an increasing and very rapidly increasing trend, with increasingly economic losses," Wahlstrom said.
"Globally, the disaster mortalities are proportionally declining because countries are getting much better at early warning systems and preparedness," she said. "But the economics of disasters is becoming a major threat to a number of countries."
From 1999 to 2011, 45,400 miles (73,000 kilometers) of roads were ripped apart by disasters in just 19 countries in Africa, Asia and Latin America, Wahlstrom said. Almost 64,000 schools were destroyed in the same time.
Fifty percent of the world's seven billion people are now exposed to disaster risks because they live in vulnerable areas, according to the UN official.