Hurricane Harvey’s second act across southern Texas is turning into an economic catastrophe -- with damages likely to stretch into tens of billions of dollars and an unusually large share of victims lacking adequate insurance, according to early estimates.

Harvey’s cost could mount to $24 billion when including the impact of relentless flooding on the labor force, power grid, transportation and other elements that support the region’s energy sector, Chuck Watson, a disaster modeler with Enki Research, said by phone on Sunday. That would place it among the top eight hurricanes to ever strike the U.S.

“A historic event is currently unfolding in Texas,” Aon Plc wrote in an alert to clients. “It will take weeks until the full scope and magnitude of the damage is realized,” and already it’s clear that “an abnormally high portion of economic damage caused by flooding will not be covered,” the insurance broker said.