It was officially a monster year for deadly US storms in 2017 with Hurricane Harvey the second most expensive hurricane on record and the final costs of Irma and Maria, both human and financial, yet to be added, according to government figures released on Thursday.

Hurricane Harvey was Texas’s most deadly in a century, killing 68, and two locations endured 5ft of rain when the tempest made landfall last August, flooding downtown Houston. All but three of the deaths were from freshwater flooding.

The storm overall caused an estimated $125bn in damage. That makes it second only to 2005’s Hurricane Katrina in financial cost. Katrina devastated New Orleans and vast areas of Louisiana and Mississippi and ended up costing $161m, when adjusted for inflation.

Harvey was the first of three gigantic hurricane-strength storms to hit the United States in 2017. Official tallies on Irma, which hit Florida hard, and Maria, which decimated Puerto Rico, both in September, are still being compiled by the National Hurricane Center, which issued its latest report on Thursday.

Hurricane Harvey spawned 57 tornadoes inland and 18 different parts of Texas were deluged with more than 4ft of rain.

“It was a once-in-a-lifetime event for so many people,” said the center’s hurricane specialist Eric Blake, lead author of the report. “I think the flooding in the Houston metropolitan area is really unparalleled.”

The government issued a range of estimates for the damage, from $90bn to $160bn, with a midpoint of $125bn.

Harvey’s maximum winds on landfall were 133mph, making it a category 5 storm.

But the really big numbers in the report were related to the torrential, relentless rain that battered the region. Government meteorologists calculated that much of the Houston metro area experienced a flood with “less than a 1-in-1000 (0.1%) chance of occurring in any given year”.

“It is unlikely that the United States has ever seen such a sizeable area of excessive tropical cyclone rainfall totals as it did from Harvey,” the report said.

The year was the hottest on record that did not include the El Niño weather pattern, and matched the record year for the most billion-dollar weather events, with climate experts saying global warming is intensifying disasters such as the triple series hurricanes.