On the last weekend of March, the Southwest's snowbanks were disappearing. Desert streams surged with runoff. The male common flickers did their springtime antics, pecking frantically on steel chimney caps to impress the girls. And the region's boatmen emerged from hibernation.

I loaded my van and drove north from Flagstaff, Ariz., across the Painted Desert. In Colorado, boatmen wound down out of the San Juan Mountains and drove southwest. Some drove south from metro Salt Lake City, speeding out from under the latest inversion layer. Others came from California, Oregon, New Mexico -- even Hawaii. We all converged near Marble Canyon, Ariz., at the Hatch River Expeditions' red sheet-metal warehouse at the base of the Vermilion Cliffs.

We camped in our vehicles, or in tents scattered over the warehouse's 11 acres, and greeted each other with enthusiastic hugs and back-thumping, laughing and hollering and hooting. The occasion? It was our annual Guides Training Seminar, which aims to educate Grand Canyon boatmen about the workplace. It was also a springtime ritual: We were renewing acquaintances and rejoining the flow of the Colorado River.

Eventually, about 250 people showed up. Saturday morning, there was a line at the coffee pot and breakfast on outdoor tables, as the high-desert weather began to vacillate between sunny warmth and icy gusts that raised the parking lot's dust. A great deal of shouting, arm-waving and whistling called us into the warehouse. Between the wall shelves that held rafts and other river gear, we settled in chairs set up on the concrete floor.

The seminar unfolded with a series of presentations by experts and notorious canyon old-timers. Scientists talked about recent findings, such as the "sedimentology of sand bars" and "humpback chub translocations," and wandered off on various scientific tangents, sharing fun facts from canyon studies: The Grand Canyon has some of the same sort of ripple structures found on Mars! That might explain a few things. ...

Generations of guides have held the seminar every spring since the mid-1970s. It was originally called the Boatman's Training Seminar, but that title fell victim to political correctness. Some years, we've gathered in an old army tent on the gorge's rim. (The tent blew down twice.) The reasons for the seminar have also evolved.

The Grand Canyon river industry coalesced in the late 1960s and early '70s, propelled by rapid growth in rafting, the Park Service's decision to limit traffic, and the development of guiding as an actual business for outfitters -- an actual job for boatmen. Back then, there were 21 river companies; most of us knew few or no boatmen from other companies, and we tended to think of "those guys" as a pack of knotheads. We were all still learning our trade. Equipment was crude; the runs through the rapids had not yet been deciphered. The early seminars helped the different clans mingle. We realized we were all in the same boat, so to speak: We all had "The River" in common.

Over the years, seven companies were gobbled up by the other 14. These days, the whole thing is more professional, though the term "boatman" is still preferred by most female as well as male guides. A small nonprofit -- Grand Canyon River Guides Inc. -- coordinates the seminar with support from the National Park Service, outfitters, a few other sponsors and ourselves.

Emily Perry, president of Grand Canyon River Guides, gave the welcoming talk. Her granddad printed the first waterproof river guides back in 1969, and her dad, O.C. Dale, stumbled into guiding. She and her sister, Ann-Marie, run big motor rigs for the Grand Canyon Expeditions Co. Both are married to boatmen.

Mike McGinnis, the park ranger in charge of the river district, updated us on changes in regulations and river terrain. On Lake Mead, for instance, where low water levels have stranded the river far from its former channel, the resulting rapid/waterfall has brought chaos and years of haggling. McGinnis explained the protocols for using a new road across the former lakebed to a takeout point above the new falls.

I wandered outside to look at old boats -- the theme of this seminar. Grand Canyon National Park has a magnificent collection of original and historic craft that plied the canyon's whitewater over the last century. Beginning about six years ago, the Park Service and nonprofit groups ramped up efforts to preserve the old boats and create a display venue. The newly formed Grand Canyon River Heritage Coalition wants to establish a River Heritage Museum at South Rim. It will have to include at least one cataract boat -- the wide-bottomed, wooden craft designed by river pioneer Norman Nevills in the 1930s. Two of them were on display at the seminar, including the Sandra, built by Nevills himself in the 1940s. Roy Webb, a University of Utah archivist, river historian and author, gave a rundown of the boat's history.

Both of Nevills' daughters were also at the seminar. And three grandsons. And a great-grandson. And Bob Rigg, who first rowed for Nevills on the Green River in 1949. In 1951, with his brother, Jim, Bob Rigg rowed through the Grand Canyon in just two and a half days -- a record that stood for nearly 30 years. In his vintage pith helmet and aviator glasses, Rigg talked about how the Sandra is now restored and back in service for annual runs with the old Nevills company. A few feet away, another pioneer, Gaylord Staveley -- Nevills' son-in-law -- was talking about the other cataract boat, dubbed the Camscott, an aluminum version that he built. Jokes and jabs flew, along with more adventure tales.

There was also a special session for rowers: the "Low Back Care and Injury Prevention/Stretching Clinic."