Firefighters say they are fully prepared to keep the Appspond Lane fire under control as bad weather grips the area.
They are regularly dampening down areas around to the giant mound of wood that is ablaze at the recycling base on the border of St Albans and Leverstock Green.
Herts Fire and Rescue Service spokesman Tom Shipp said: “We have already had winds of up to 40mph, which spread the burning embers around the site.
“This is why we have got crews there all the time, to make sure the fires do not spread to any unaffected areas.”
Even the constant rain that began on Tuesday has failed to put out the fire, which has been burning since Saturday, November 10.
Crew commander David Chatfield, from Hemel Hempstead Fire Station, said: “The rain will have had some effect, but it is so deep-seated the rain that reached the surface of the heap would not have reached the centre of it.”