1. Climate change. The Earth's climate is warming, and this is leading to longer and more intense droughts. Droughts make vegetation more flammable, and they also create ideal conditions for wildfires to spread.

2. Land use changes. Humans are increasingly converting forests and other natural areas into development. This fragmentation of natural landscapes makes it easier for wildfires to spread, and it also creates more opportunities for human-caused ignitions.

3. Increased ignitions. The number of human-caused wildfires is increasing. This is due to a number of factors, including more people living in fire-prone areas, more recreational use of wildlands, and more electrical infrastructure in fire-prone areas.

4. Fire suppression. For many years, firefighters have been successful in suppressing wildfires. This has led to a build-up of fuels in many forests and other natural areas. These fuels provide more material for wildfires to burn, and they can make fires harder to control.

These four factors are all contributing to the increasing danger of wildfires. As a result, wildfires are becoming more destructive, more expensive to fight, and more difficult to control.