Because of the strong sunlight, small fires were difficult to detect until they have taken hold. This is why the fire spread from Gammelholm to the main magazine along Holmens Canal (Holmens Kanal Danish) and over Holmens Canal to the quarter around Saint Nicolai Church and from there, along Gammel Strand to the area around Nytorv/Gammeltorv.
The intense sunlight made it challenging to notice small fires until they had grown. As a result, the fire spread from Gammelholm to the main magazine via Holmens Canal (Holmens Kanal Danish), then across the canal to the Saint Nicolai Church quarter, and eventually along Gammel Strand to the Nytorv/Gammeltorv area.