Corpus Christi - The National Hurricane Center says Hurricane Harvey's maximum sustained winds have decreased to about 75 mph (120 kph) and that the storm is now centred about 25 miles west of Victoria, Texas. The centre says in its 10:00 update that the storm is expected to weaken over the next 48 hours and to become a tropical storm by Saturday afternoon. The storm is moving north at 2 mph (3 kph). The hurricane centre says that although the winds are weakening, the storm could cause catastrophic flooding over the coming days.Harvey came ashore in Texas on Friday night as the strongest hurricane to hit the US in more than a decade. The Coast Guard has sent two helicopters to try to rescue the crews of three tugboats in distress near the Lydia Ann Channel near Port Aransas, Texas. Two MH-65 Dolphin helicopter aircrews have been sent to rescue the crews. Harvey has knocked out power to nearly 300 000 customers along the Texas coast and has dumped nearly half a meter of rain in some places. The Electric Reliability Council of Texas, which manages about 90% of the state's electric grid, says there were 211 000 outages in the few hours after Harvey made landfall Friday night as a Category 4 hurricane. That figure rose to 293 000 on Saturday, when the hurricane was downgraded to Category 1. In addition to a loss of power, emergency personnel in the communities northeast of Corpus Christi where Harvey made landfall are reporting a loss of cellphone service and other forms of communication.