It is anticipated that up to a month's worth of rain could fall over a 24-hour period.
The Met Office has issued an amber, or medium risk warning, which will be in place until 23:59 BST on Thursday.
Residents are being warned to stay vigilant and listen out for weather and local area updates.
At Honister Pass on the B5289 in the Borrowdale Valley, some 12.1 inches of rain was recorded in the 24 hours up to 3am this morning, close to the all-time UK 24-hour rainfall record of 13.4 inches set at Honister Pass during Storm Desmond.
Residents in Kendal have reported that the River Ken has risen dangerously since yesterday.
Flood warnings - meaning flooding is expected - are in place for parts of Keswick, Grasmere, White Bridge, Stock Lane, Burneside, Steeles Row and Carling Steps, where river levels have risen.
More to follow.