Texans are bracing themselves for a spell of ultra-cold weather and fear blackouts in the days ahead, despite assurances from state leaders that, unlike previous winters, their grid is adequately prepared to withstand days of frigid temperatures.

The Electric Reliability Council of Texas, or ERCOT, which manages the grid for roughly 90% of the state, issued an updated winter warning Friday stretching from Sunday through Wednesday, when officials said they expect “extreme cold weather” to barrel through the state, resulting in “higher electrical demand and the potential for lower reserves.”