1. Contact your insurance company: Notify your insurance company as soon as possible. Provide them with the necessary details about the flood, including the location, date, and extent of the damage.

2. Document the damage: Take photos or videos of your vehicle from multiple angles to provide evidence of the flood damage. Make sure to capture any visible damage to the exterior and interior of the car, including the engine and mechanical components.

3. File a police report: If your car was severely damaged, it is advisable to file a police report. This report will serve as additional supporting evidence for your insurance claim.

4. Take necessary precautions to prevent further damage: If it is safe to do so, take steps to prevent any further damage to your vehicle. This may include moving it to a dry and secure location or covering it with a tarp.

5. Provide all necessary documentation: Fill out the necessary claim forms provided by your insurance company. Ensure that you include all required documents, such as the police report, photographs/videos of the damage, and any relevant invoices or receipts for repairs.

6. Cooperate with the insurance company: Respond promptly to any requests for additional information or documentation from your insurance company. Keep all communication and correspondence regarding your claim organized for reference.

7. Schedule a vehicle inspection: Your insurance company may require an inspection of your vehicle to assess the extent of the damage caused by the flood. Schedule this inspection promptly and provide access to your car along with all required documents.

8. Determine the claim amount: Once the inspection is completed, the insurance company will evaluate the extent of the damage and determine the eligible claim amount based on the terms of your policy.

9. Repair your vehicle: If your claim is approved, you may choose to have your vehicle repaired by a trusted repair shop. Ensure that the repairs are carried out by authorized professionals who can provide detailed invoices.

10. Follow up on the claim: Stay in touch with your insurance company to process any outstanding payment or provide any additional information required to finalize the claim.

Remember, the specific steps and requirements for claiming car insurance due to a natural flood may vary based on your insurance company and policy. It is essential to review your policy thoroughly, seek clarification from your insurance provider if needed, and follow their instructions throughout the claim process.