Mortgage delinquencies surged in September, bringing the largest single-month delinquency spike in a decade, according to the latest First Look data report from Black Knight.

Mortgage delinquencies soared by 13.2% in September, the largest monthly spike since November 2008, the report showed. This brought the total U.S. delinquency rate to 3.97%.

Black Knight explained three factors contributed to the increase in mortgage delinquencies, all hitting the month at once.

Typically, September sees an increase in mortgage delinquencies. Of the past 19 Septembers, 16 saw mortgage delinquencies increase with an average rise of 5.2%. This is the largest average for any month during the year.

The second factor that made mortgage delinquencies spike was that the month ended on a Sunday, which typically creates strong upward pressure on delinquencies, according to the report.

And finally, Hurricane Florence, which swept through the Eastern U.S. in September, caused delinquencies to spike by 38% month-over-month in the areas it touched. Already more than 6,000 borrowers have missed a payment as a direct result of the storm.

But the report did have positive news for the mortgage market. Foreclosure starts plummeted 15.1% from August to nearly an 18-year low. This was also down 11.5% from September 2017. The month’s double-digit decline brought foreclosure starts to just 40,000 for the month.

Also, both the inventory of loans in active foreclosure and the foreclosure rate fell below their pre-recession averages for the first time since the financial crisis.