AUSTIN, Texas—A huge swath of the U.S. braced Tuesday for a major winter storm that was expected to dump heavy snow in the Rockies, ice highways, disrupt travel across the Midwest and plunge temperatures below freezing in Texas. The blast of winter weather comes nearly a year after a catastrophic freeze that devastated Texas’ power grid and knocked power out for days, causing hundreds of deaths in one of the worst blackouts in U.S. history. The forecast this week, however, does not call for the same prolonged and frigid temperatures like the February 2021 storm. “No one can guarantee that there won’t be any” outages caused by demand on the grid, Texas Gov. Greg Abbott said during a briefing in Austin, where state officials defended their readiness for the days ahead. “But what we will work to achieve, and what we’re prepared to achieve is that power is going to …