The sea is mostly ice-covered, and the Thwaites Ice Tongue protrudes into it. The ice-covered area of the sea, averaging about 3 km (2 miles) in thickness and roughly the size of the state of Texas, is called the Amundsen Sea Embayment; it forms one of the three major ice drainage basins of the West Antarctic Ice Sheet, the others being the Ross Sea Embayment and the Weddell Sea Embayment. In March 2007, scientists studying the ASE through satellite and airborne surveys announced a significant thinning of the ASE, due to shifts in wind patterns that allow warmer waters to flow beneath the ice sheet.