A River Runs Through It

Review: River Run (Forensic Geology Series Book 5) by Toni Dwiggins

Cassie Oldfield and Walter Shaws, the forensic geologists we met in Badwater, Quicksilver, and Volcano Watch (reviewed here in December 2013's Truth as Solid As Rock) and again in Skeleton Sea (reviewed here as Hematite and Franciscan Melange in May 2015) are back again with a mystery set in the awe-inspiring canyon walls that tower above the Colorado River.

There are many ways to die on the river, as this novel states from the outset. Our geologists, in the area to supply their expertise for a documentary film about the Colorado, are tapped to help solve the puzzle when a fishing party of four is lost from a raft found adrift on the river. Grand Canyon Park rangers hope they can narrow the search area based on a baggie of rock chips left on the raft, and recover the lost rafters alive.

The mystery deepens when the raft party leader, Reid Lassen, is found alive. He was the only one of the four in his party wearing a PFD (personal flotation device). Reid's an old geologist friend of Walter Shaws, but Walter had been told he was dead, decades before. And he can't help with the search for the other rafters, because he's got amnesia. So Cassie and Walter go back to searching for rock sources, including one for a new specimen found in the cargo pocket of a rafter who didn't survive. 

Every new specimen serves only to widen the search area. And time is running out for survivors who have yet to be found.

The action of the novel switches breath-takingly from geology to techniques of river rafting and suspicions of eco-terror. It's exactly like a raft trip through Class Ten rapids on the Colorado: terrifying, engrossing, thrilling, and exciting at turns (and sometimes all four simultaneously.)

As with the other novels in the series, River Run succeeds in making the science accessible and integrating the experience of field geology with the needs of ordinary people. In this story, these are all the water-using groups along the river's run: park rangers, rafters and canyon hikers, ranchers and farmers, communities and resorts.

Read it as a mystery; read it as a thriller; read it as science/fiction in the best sense of that term—but read it!