Nightly News | September 22, 2012
>> the pacific northwest is on alert over what's being called the largest fire event in years, burning well beyond the traditional fire season. there are warnings for families far outside the fire zone as clouds of smoke are spreading. kristen dahlgren has the report.
>> you can want get there this way due to the fire.
>> reporter: as washington state 's wildfires continue to burn out of control, the raging flames are only part of the problem.
>> i grew up here. i have worked here for six years and haven't seen it this bad.
>> reporter: smoke so thick dozens have been taken to hospitals for treatment. in many areas schools are closed and residents are warned to relocate, stay inside, wear masks.
>> it is in the hazardous range and it is three times worse than any other forest fire that we have measured since the 1980s .
>> reporter: these nasa photos show the fires in the pacific northwest . the smoke spreading so far the haze is visible thousands of miles away over the atlantic ocean .
>> good air quality is measured at zero. we start at zero. we start getting into the unhealthy range at 35. we spoked into 900 plus. sometimes the monitors are knocked off there's been so much smoke.
>> reporter: in washington state the two largest fires are forecasted to merge into a blaze bigger than seattle. red flag warnings are posted as more dry lightning is in the forecast. cooler fall nights only mean the smoke becomes trapped in low lying valleys.
>> the fire has been growing during the nighttime hours.
>> reporter: a dangerous combination as firefighters battle flames and breathe in thick smoke. but experts say the merging fires could hepburn ealp burn each other out and an approaching front could bring moisture, a tiny glimmer of hope in what is now a sky thick with smoke. kristen dahlgren, nbc news.