It was a lesson that should have been taken to heart after the northern Utah floods of 1983, when one town, Thistle, was wiped off the map and Salt Lake City streets were turned into makeshift canals to handle overflowing creeks.

But did we learn? Almost 22 years later, the short answer is: Sort of.

Wasatch Front communities, particularly in Salt Lake County, have taken great pains over the past two decades to prevent a repeat of 1983, clearing and widening channels, creating drainage basins and toughening zoning and building codes in a bid to minimize flood-related damage when the waters come crashing downstream once again.

Yet the reality is, because so much of Utah's population lives in areas considered to be flood-prone - at the base of canyons, in river basins and near large bodies of water - think Great Salt Lake and Utah Lake - that many residents remain vulnerable to the threat. Look only at all those starter castles perched high up on the benches, where mudslides can occur, or the new subdivisions popping up around places like the Jordan River.

"Development has exploded in Utah," says Judy Watanabe, the state's flood plain manager, "and unfortunately, a lot of it has happened in flood plains. So this scenario could play out almost anywhere."

Are these foolhardy homeowners? Negligent city planners? Flood control officials won't go that far. But if you do build in those areas, they say, remember one thing: There are no 100 percent guarantees.

"We see lots of instances where folks try and do the right thing and and put in safeguards - retention basins, diversions and channels," says Scott Stoddard, Intermountain Region representative for the U.S. Army Corps of Engineers. "The problem is, Mother Nature doesn't sign off on any given design. So no matter how long, how high and how big the improvements are, there's still an element of risk there. Granted, it's greatly minimized, but it's still there."

Or, as Watanabe puts it, "If you're moving to Swift River Drive or Muddy Creek Avenue, you'd better understand the risks and responsibilities."

Utah's early settlers never faced these issues, according to Stoddard, because most had the good sense to build their cabins well above or well away from the water - close enough to get to it, but far enough away to avoid the consequences when the floods and mudslides came.

But those common-sense standards began to erode as the Wasatch Front and the rest of the state continued to grow. As cities and towns sprung up, they overran the rivers and creeks that residents had once built away from. And the infrastructure constructed to accommodate all those residents and protect them against high-water-flow years proved inadequate. Salt Lake City experienced major flooding in 1952, and the '83 floods topped that - 13 of the state's 29 counties were declared disaster areas, cleanup costs topped $200 million and one person died.

"We learned a lot from that," says Salt Lake County public works engineer Chris Springer, who experienced the '83 floods as a relief worker and now works in the flood-control department. "Since 1983, we've been taking monies from county coffers and budgeting them out for various flood-control projects. Over the last 20 years, we've been doing a lot of little things throughout the county. If we wind up with 400 inches of snowpack, we may end up flooding somewhat, but it won't be like before because of all the protection measures that have been put in place."

Still, notes state flood plain manager Watanabe, not everyone has gotten with the program. Though virtually all of the state's counties participate in the Federal Emergency Management Agency's flood-insurance program - communities receiving FEMA funds require flood insurance for any home built in a flood plain - there are still holdouts. The city of Springdale, adjacent to Zion National Park, is one, she says. Unincorporated Grand County, through which the Colorado River flows, is another.

Given the state's recent flood history, "that's kind of astonishing," says Watanabe. "There is a lot of misunderstanding about the flood-insurance program. There's a fear of regulation. But it's really to their benefit. We live in the desert, not the Mississippi River Valley, but we still get our share of floods; certainly more floods than earthquakes. It's a hazard we have to live with."

The question now is, are we going to have to live with it this spring? Could 1983-type stream flows come cascading down the Cottonwood canyons and City Creek come May?

Possibly, but not likely, says Brian McInerney, a National Weather Service hydrologist.

Yes, current snowpack totals in northern Utah are roughly in line with what they were 22 years ago. But the snow kept piling up through the spring of 1983, and lower-than-normal temperatures kept it trapped in the mountains. Then, over the Memorial Day weekend, summer arrived, bringing 90-degree days. That snowpack came down - all at once.

A recurrence, McInerney says, "Is highly unlikely. We'd have to keep adding to the snowpack in May, then in a 24-hour period, change the weather from cold to hot and sunny. That's a real long shot - though, if you were to keep adding snowpack into the spring, the chances of reaching those high temperatures becomes more likely."

Even if Wasatch Front residents don't witness a repeat of '83, McInerney thinks they could still see some things this spring that they haven't seen for awhile.

"We haven't had a good flushing to blow out all of the chunks in the channel for a good six years," he says. "That will be a problem if we have a good runoff this year. We could have lots of trees and brush coming down. But at this point, it's still too early to tell. We really don't know what's going to happen."

In any case, U.S. Army Corps of Engineers representative Stoddard says last week's events should, if nothing else, shake Utahns out of their high-and-dry stupor. The long-held concept of the "100-year flood," he says, is a myth.

"People who have been through a 100-year flood think they won't have to deal with it again in their lifetime, and that couldn't be further from the truth," Stoddard says.

"A 100-year flood, in a probability sense, means there is a 1 percent chance a flood can happen in any given year. But we had back-to-back 100-year events in 1983 and 1984. It's possible to have multiple 100-year floods at a time. It's something people need to know and be aware of."

jbaird@sltrib.com