The National Insurance Crime Bureau (NICB) is warning Illinois property owners to be alert for contractor fraud as recovery continues from a series of severe weather events that caused widespread damage across northern Illinois.

The advisory follows a June 10 derecho that produced wind gusts of up to 85 mph and widespread damage across much of northern Illinois, according to the National Weather Service. A day later, multiple tornadoes, destructive straight-line winds and heavy rainfall caused additional damage and flooding concerns in parts of the Chicago metro area and northern Illinois.

Illinois has recorded 140 tornadoes this year, according to the NICB, far exceeding the state's annual average of 54.

The organization said fraud schemes frequently emerge after natural disasters, targeting homeowners and business owners seeking repairs. Common scams may involve offers for roof repairs, debris removal, water mitigation, reconstruction and other storm-recovery services.

Related: The Honest Roofer's Playbook for Post-Storm Trust

"After destructive storms, most families and businesses want to start the recovery process as soon as possible," said NICB President and CEO David Glawe. "This is when home and business owners must be most vigilant, as fraudsters use this opportunity to swoop in."

NICB advises property owners to contact their insurance carrier before beginning repairs and to verify the credentials of contractors. Warning signs may include unsolicited offers immediately after a storm, claims of affiliation with insurance companies, high-pressure sales tactics, demands for cash payments, requests for full payment before work begins and offers to waive insurance deductibles.

The organization also recommends obtaining multiple estimates, checking references and ensuring all project details are included in a written contract before work begins.

NICB said it works with law enforcement agencies and insurance companies to identify and prevent fraud following severe weather events.