Exactly. Insurance companies know they'll have to pay out their policies are already designed with 1, 2 or even 3 years of inclement weather in mind. They don't need to reprice to cover that. They need to reprice because the inclement weather is becoming standard and the severe weather becoming worse. They've got the data already in their own payouts, they most likely can already see the trend.
Insurance companies can prepare for the future by hiking prices to cover more/larger payouts, but if other companies don't think that'll happen they can undercut and steal their clients.
Insurance company can also prepare for the future by gaining more clients over larger areas spreading risk among a bigger pool. The best way to do this is to have the lowest rates, so there is an incentive to get the prices right. Too high and they lose clients, too low and they can't cover payouts and go out of business.
The fact that it appears all insurance companies are doing this either means massive industry wide collusion, or they all agree with the scientists predictions.