Yosemite National Park is closed through at least March 16th. A partial reopening on March 17th is a best-case scenario. You can check the National Park Services webpage for latest information/current status.
Update: Yosemite National Park opened March 20th with limited services and access via Highway 140 only. Several miles of pedestrian paths in Yosemite Valley are plowed, but all hiking trails are covered in snow.
The park closure is the result of winter storms that dropped up to 15 feet of snow. More snow is forecast for this week. An indefinite closure is in place as park crews work to restore critical services and make it safe for visitors to return.