During last weekend’s rains the clear waters of the Cache la Poudre River turned oily black and stream cobbles disappeared under several inches of roiling ash from the High Park fire.

A black sludge now coats many river shores once sparkling with white, tan or pink sands. A canyon once heavily scented by pines smells like a smoky campfire.

Many miles of this 126-mile-long river now evoke its namesake, the gunpowder buried by French trappers along its banks in the 1820s.

People now enjoy “blackwater rafting,” observed homeowner Mike Smith, whose deck juts over the Poudre.

The water was beginning to clear midweek, and other changes in this wild and scenic river will be short-lived. Yet scientists say other effects of a fire that burned across 87,284 acres between June 9 and early July will last longer and hurt more.

Read more about the fire-damaged Cache la Poudre River and see a video of the sludge.