Most days this autumn, Rocky Mountain National Park (RMNP), Estes Valley, and Estes Park have been "blessed" with various levels of haze. Recently and rarely, a cold front and high pressure ridge brought clean air to these locales - as illustrated in the left photo. In contrast, various levels of haze are usually present and visible. The photo on the right was taken on one of the worst haze days this fall.

The purpose here is not to present a same-time timeline of photos but instead is to present end points of clarity and cleanliness in contrast with reduced clarity and injurious air.

Clean air, clear vision days used to be far more common in Rocky and Estes. I and some others have begun to curtail hiking on haze-filled days, because particulates and ozone are associated with lung pathology.