The February freeze that crippled the Texas energy grid for days amplified a trend already well underway — high-cost and increasingly frequent climate-related disasters that the electric power industry struggles to manage through.

That assessment comes in a new report from energy lender CoBank, based in Denver.

The polar outbreak affected several states, requiring rolling outages, but it paralyzed Texas because natural gas pipelines and other critical infrastructure were not designed to withstand extreme cold. An estimated five million people lost electricity for prolonged periods in a handful of southern states battered by the storm, the bulk of them in Texas.

“In the end, the Texas blackouts were the largest forced power outages in U.S. history and may prove the costliest...