Roundup: How Ida gained strength / BRAC survey / Delta peak  

    Storm accelerant: As Hurricane Ida headed into the Gulf of Mexico, a team of scientists was closely watching a giant, slowly swirling pool of warm water directly ahead in its path, The Conversation reports. That warm pool, an eddy, was around 125 miles across, and it was about to give Ida the power boost that in the span of less than 24 hours would turn it from a weak hurricane into the dangerous Category 4 storm that slammed into Louisiana. Read more about how this warm pool formed and impacted the storm. 

    Business impact: The Baton Rouge Area Chamber today released a preliminary analysis of responses to its Hurricane Ida business impact survey. So far, 73 regional businesses have submitted responses to the survey, with 64% saying the storm had a significant impact on their operations. The survey is open until noon Thursday. Submit responses here. 

    Virus wave: The number of new daily U.S. COVID-19 cases has risen less over the past week than at any point since June, The New York Times reports, signaling the fourth surge of infections may have reached its peak. Since the pandemic began, coronavirus cases have followed a strange two-month cycle. In one country after another, the number of new cases has often surged for roughly two months before starting to fall. Read the full story.