Greater Manchester Fire Service said tyres have caught light and are causing the billowing smoke across the area.
Three fire engines are at the scene, close to a railway line near Broughton Road, Salford.
Several people spotted smoke in the Salford area - we are dealing with a caravan on fire
More top news
Wet and windy for the next 24 hours... or longer!
Merseyside Police want to speak to teenager described as "significant witness" after stabbing on Friday morning
Moderate counts for the next few days, rising in any brighter spells