A combination of dry air and gusty winds will increase the risk of fires across a large part of the U.S. West and northern Plains this week, forecasters said. Parts of more than a dozen states will experience dangerous conditions for fire ignition and growth through Wednesday, with relative humidity levels less than 20 percent and wind gusts over 20 mph, AccuWeather.com reported. A long period of dry weather has created plenty of dried vegetation and leaves that could provide ample fuel for any fire, forecasters said. A cold front coming south from Canada into the northern Rockies and High Plains is the biggest factor for fire risk, as it is enhancing winds both ahead of it out of the southwest, and behind it from the northwest, they said. Moisture should eventually follow the frontal passage into parts of Idaho, Montana, Wyoming and the Dakotas, but it could be delayed for up to a day, they said. However, the moisture will never make it to California where days of near-record heat is keeping fire risk dangerously high, the forecasters said.