The Allstate Corporation (NYSE: ALL) began today’s trading in the red, after it announced estimated catastrophe losses for the month of August of $272 million or $215 million, after-tax, including favorable reserve reestimates for prior period events.Catastrophe losses for August include 15 events estimated at $306 million, with approximately $75 million related to a hail event in Calgary, Canada. The Calgary hail event estimate includes reinsurance reinstatement premiums and is net of anticipated reinsurance recoveries of $225 million.Total catastrophe losses for July and August were $814…