Hurricane Ike, which made landfall on the Texas island of Galveston on Sunday, will cause insured losses of between $US6 billion ($7.2 billion) and $US16 billion ($19.4 billion), according to early estimates by Risk Management Solutions (RMS).

The catastrophe risk agency says widespread damage has been suffered by buildings in coastal areas and high-rise buildings in downtown Houston as a result of roof and window damage.  

Homeland Security Secretary Michael Chertoff says 2.2 million Texans were evacuated and more than 130,000 left Louisiana ahead of the storm.

Hurricane Ike is now a tropical depression, heading into the northern US with heavy rainfall and strong winds.

The coastal storm surge from Ike caused flooding of up to seven metres along the Texas coast.  The hurricane passed within 32km of Houston International Airport, which has since been reopened.

Nearly 2000 storm victims have been rescued in the course of nearly 500 search and rescue missions.

Despite two floating drilling rigs breaking free in the Gulf of Mexico, oil and gas operators inspecting the 717 platforms in the gulf expect to have production restored quickly. Fifteen refineries in Texas and Louisiana were shut down.

Texas has already been hit by Hurricane Dolly in July and Tropical Storm Edouard in August. While Hurricane Gustav threatened the state last week, it made landfall next door in Louisiana. Many insurers are still dealing with claims from Hurricane Dolly that caused about $US500 million ($608 million) in insured losses.

The degree of flooding and business interruption that was predicted to occur with Hurricane Gustav has been considerably less than initially feared. RMS has revised its initial industry loss estimate for Gustav from $US4-10 billion ($4.8-12 billion) to between US$2.5-4.5 billion ($3-6 billion).