Telephone lines and power transmission were knocked out in many areas in the west hit by the storm and around 8,000 people were evacuated from flood-threatened areas in Pinar del Rio province as Katrina passed to the north.
The coastal city of Surgidero de Batabano south of Havana was 90 percent under water, according to Cuban television reports.
The category-five hurricane on the Saffir-Simpson scale carried winds of 250 kilometers per hour (155 mph) as it moved Sunday from the southwest Florida coast towards New Orleans and the US state of Louisiana, according to the US National Hurricane Center in Miami.
The Cuba Institute of Meteorology warned that heavy rains and waves would continue to hit western Cuba through Sunday, causing flooding along the island's northwest coast.
It also warned that high winds and waves continued to pose a danger for ships in the region.