Wildfire alert for dry and windy fire season.

With a month to go for the peak California wildfire season, insured losses already surpassed $1 billion in September – the costliest and most damaging for the U.S. in eight years, according to Impact Forecasting.

Wildfires destroyed more than 2,000 homes in California during September, the catastrophe model development arm of Aon Benfield noted in its monthly Global Catastrophe Recap report. The damage breaks down into two major events.

The Valley Fire, which hit northwest of San Francisco, is the third most damaging wildfire in state history. According to Impact Forecasting, it killed four people and destroyed 1,958 homes and other structures. Economic losses from the fire surpass $1.5 billion, according to estimates, with insured losses surpassing $925 million.

The Butte Fire, which broke out southeast of Sacramento, with the 7th most damaging wildfire in state history. It killed two people and caused more than $450 million in estimated economic losses. Insurance losses are expected to be above $225 million.

Peak California wildfire season began in late September and is expected to last through early November. It’s already made the record books, causing more U.S. damage and financial loss that’s the highest it’s been since 2007.

Impact Forecasting noted a number of other catastrophe events in September, including:

Indonesia wildfires, considered the worst since 1997. Estimates place the damage at $4 billion in direct and secondary economic losses from fires in Sumatra and Kalimantan. Separately, a magnitude 6.6 earthquake hit eastern Indonesia on Sept. 25, injuring dozens of people, plus damaging or destroying nearly 2,500 homes and other structures.

On Sept. 16, a magnitude 8.3 earthquake hit Central Chile. A tsunami followed, killing 14 people, and more than 1 million residents were evacuated. Estimated economic losses near $1 billion.

Japan is reeling from extensive flooding that hit parts of the country, killing 8 people and either damaging or destroying 20,000 homes. Three large insurers in Japan estimate payouts of at least $250 million.

Drought worsened across western Canada. Annual insurance claims in Alberta alone could reach $675 million, and national economic losses have surpassed $1 billion.

Source: Impact Forecasting/Aon Benfield