To prevent damage to the wind turbine the wind turbines are shut down at wind speeds of 55 MPH.
Wind turbines are made so that the wind turbines shut down automatically once they get to a wind speed of 55 MPH.
High wind speeds can cause the wind turbines to generate too much electricity and can cause the wind turbine blades to break off as well.
So to prevent damage the wind turbine blades shut down at 55 MPH and stay shut down until the wind speeds drop below 55 MPH.
Wind turbines cost a lot of money so they must be protected from damage.