A series of 100+ degree days across Oregon in the past week and lightning storms that swept across the region have caused fires across the state to start or grow. The Pilot Rock Fire near the town in Umatilla County is the latest to spark, quickly reaching more than 20,000 acres burned as of 6 a.m. Thursday, according to the Sheriff’s Office. While the fires have not reached major population centers so far, they have degraded air quality in some parts of the state. People living in Bend saw their air dip to very unhealthy levels in the early hours of Thursday morning. The fires in Southern and Eastern Oregon have also proven to be a dramatic turn from cooler, wetter weather in the spring that kept fire danger low. According to state fire officials, thousands of residences in Harney, Wasco, Morrow and Jackson counties have the potential to be threatened by fires currently burning.