California Coast & Ocean

May 22, 2007--the day we've been waiting for--has dawned glorious. But it's not the sunshine that fills us with joy. It's the half-foot minus tide, which means the upper edges of Monterey Bay will be a little less sloshy than usual. It is a perfect morning for a treasure hunt.

I check to make sure that my knapsack is ready, with GPSr (global positioning system receiver), plenty of spare AA batteries, and a Ziploc goody bag full of knickknacks. A camera too--you never know when the hunt will take you somewhere unexpectedly beautiful or interesting. And last but not least, a sheaf of clues.

Our tick-list today features two prominent spots that we've been to but have not been able to check out because they are usually under water, or at least wave-swept. We had stored both in the GPSr as latitude-longitude readings ("waypoints"), and since then have been waiting for a minus tide. Today they will be within our reach. One of them, at the tip of the Monterey Peninsula in Pacific Grove, is usually an island; the second, a crumbling 20-foot-high structure left over from the Cannery Row heyday--perhaps a former pump station--is sometimes at the water's edge but more often sloshed by waves. Both promise special rewards--assuming our searches prove successful.

What is it we seek? Tupperware and old ammo cans, or, on the "micro" end of the spectrum, test tubes, film cans, and Altoids tins. The containers vary, as does the treasure stashed inside (think shiny colored objects or at the very least a minuscule logbook), but we can always be assured of finding something. If, that is, our skills of navigation and observation are up to the task.

The pastime we've become addicted to is called geocaching: geo- as in earth (it's a worldwide hobby, with more than 410,000 caches in 222 countries worldwide, and it also takes place out in the world--a definite plus); and -caching, as in squirreling something away; and it takes you out into the world on a glorified scavenger hunt among tens of thousands of strangers.

Geocaching is a game made possible by military surveillance, including satellite-enhanced position finding--something that was available to civilians only in an intentionally degraded form until May 2, 2000. On that day, a mythical "great blue switch" was flipped, and in an instant the accuracy of GPS technology improved tenfold as 24 satellites processed new orders and allowed backpackers, boaters, scientists, and other citizen users to join the military in gaining pinpoint positioning accuracy.

The move itself was not entirely unexpected. The White House had earlier declared its intention to cease data degradation eventually--say by 2006. For the "switch" to be pulled six years early--and announced by President Bill Clinton's press secretary just one day before the fact--came as a total surprise. Internet technogeek newsgroup sites immediately sizzled with ideas on how to take advantage of the new capability.

One GPS enthusiast, David Ulmer of Beaver Creek, Oregon, decided to put it to an immediate test. On May 3, 2000, he posted a notice on a GPS users' bulletin board, sci.geo.satellite-nav, saying he had stashed a bucket in the woods and its contents were a logbook and pencil, as well as such goodies as videos, software, and a slingshot. He gave these coordinates of his cache, read from his now more powerful GPS device: N45°17.460 W122°24.800. "Take some stuff, leave some stuff," he invited anyone interested. And so the Great American GPS Stash Hunt was born, redubbed "geocaching" within a few months.

As one wag noted on a keychain we found early on, "We use multimillion-dollar military satellite systems to find Tupperware in the woods. What do you do?"