Cumbria Police say the A66 will remain closed at Threlkeld "for the foreseeable future".
Diversions are in place.
People travelling from Keswick are asked to travel along St Johns in the Vale.
Those travelling from Penrith, will be turned round at Rheged and are advised to use the M6 routes.
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Kerrie brings you Sunday night's forecast
The highest risk of snow is from the NW later on Monday into Tuesday. For all it will remain cold with raw days and frosty, icy nights
Wintry start for some and windy. Brightening later