Teesdale is a dale, or valley, in Northern England. The dale is in the River Tees’s drainage basin, most water flows stem from or converge into said river, including the Skerne and Leven. Upper Teesdale, more commonly just Teesdale, falls between the Durham and Yorkshire Dales. Large parts of Upper Teesdale are in the North Pennines AONB (Area of Outstanding Natural Beauty) - the second largest AONB in England and Wales. The River Tees rises below Cross Fell, the highest hill in the Pennines at 2,930 feet (890 m), and its uppermost valley is remote and high. The local climate was scientifically classified as "Sub-Arctic" and snow has sometimes lain on Cross Fell into June (there is an alpine ski area Yad Moss).