Residents of Hawaiʻi’s Big Island faced a hurricane watch Friday, Sept. 25, as Hurricane Nolo moved toward the islands with forecasters warning that slow-moving rain bands could cause life-threatening floods and landslides. Maui was under a tropical storm watch. The National Hurricane Center said hurricane conditions could occur on the Big Island within 24 to 36 hours. Nolo was expected to become a major hurricane over the weekend, although the forecast did not call for the storm to make landfall. As of Friday morning, Nolo had maximum sustained winds near 85 mph and was moving north-northeast at about 5 mph. Forecasters expected it to slow, turn west and then pick up speed Saturday and Sunday. Warm ocean water could help the storm’s winds climb to 140 mph over the next 72 hours, a Category 4 intensity. Rainfall poses a major danger even without a direct hit. Forecast totals ranged from 10 to 25 inches across a broad area, with some locations potentially receiving more than 2 feet. The hurricane center warned that the downpours could trigger catastrophic flooding and mudslides, particularly on steep terrain. The heaviest rain was expected in eastern and southern parts of the Big Island; Maui could receive as much as 10 inches. Hawaiʻi and Maui counties opened shelters for people and pets, and schools and government offices began closing Thursday, according to Hawaiʻi Public Radio. The preparations follow a difficult stretch: Hurricane Lala passed close to several islands in mid-August, Tropical Storm Moke followed about a week later, and Hurricane Lowell struck Kauaʻi and other areas in early September. Nolo’s track has shifted sharply. After moving west over open ocean earlier in the week, the storm turned north toward the Big Island. It had also briefly weakened: forecasters had said last week that the system was dissipating, but resumed advisories after it regenerated as a tropical depression, then strengthened into a tropical storm and hurricane. The storm is part of an active Pacific hurricane season unfolding alongside a powerful El Niño. The immediate concern for island communities is Nolo’s combination of heavy rainfall and slow movement, which can prolong exposure to flooding and slope failures even if the storm stays offshore.