]]> http://blog.sdcmountainworks.com/2010/04/14/monarch-snow-cats-by-gino-penasa/feed/ 0 Sangre de Cristo Mountain Works Cat Trip cat trip too http://blog.sdcmountainworks.com/2010/02/02/avalanche-beacons-getting-the-drift-by-bob-lee/ http://blog.sdcmountainworks.com/2010/02/02/avalanche-beacons-getting-the-drift-by-bob-lee/#comments Tue, 02 Feb 2010 21:55:58 +0000 Sangre de Cristo Mountain Works http://blog.sdcmountainworks.com/?p=453 ]]> These days just about every backcountry snow traveler who is serious, savvy, and responsible has an avalanche beacon, those small radio transceivers that give a buried avalanche victim a chance of being recovered alive by sending out a signal that can be tracked and pinpointed by the other members of the group.  Everyone that ventures into snow-covered terrain that’s steeper than a meadow should own a beacon, as well as a shovel and probe.

Using an avalanche beacon to find another one is a combination of science and art, as is snow analysis and winter backcountry travel in general.  Avalanche awareness and training classes are invaluable information sources for people that want to get out into the backcountry during winter and there are a number of good primers and tutorials online.  Links to some of those can be found at the end of this piece.

But what I want to write about here is a problem with older or traumatized beacons that many users may not be aware of – frequency drift.  First, a little background: The earliest avalanche beacons came on the market in 1973 and transmitted a signal at 2.275kHz.  For a while 2.275 kHz was the North American standard and 477 kHz was the standard in Europe.  In 1997, the 2.275 kHz frequency was totally abandoned in favor of the current 457 kHz standard,  The two frequencies are not compatible and any 2.275 kHz beacons still in use are obsolete and need to be retired immediately.

Currently there are two modes of beacons.  Analog beacons use an audible beep and (usually) a visual display that get stronger as the receiving beacon approaches the transmitting beacon.  Digital beacons use multiple antennas and digital processing for a display that shows the direction and distance to a buried beacon.  Some beacons combine both analog and digital modes to make use of the benefits of each – analog signals have more range, digital processing helps to locate victims more quickly.

Back on the issue of frequency drift, a fairly recent study by Bruce Edgerly and John Hereford – linked below – found that modern digital beacons may not be able to receive signals from older and heavily used beacons because 1) the older beacons may be transmitting signals that have “drifted” off from the designated frequency and 2) the demands of digital signal processing require some “narrowing” of the range of frequency a digital beacon can receive.  The study can be found at:
http://beaconreviews.com/transceivers/pdfs/Frequency_BCA.pdf

A somewhat less scholarly (and easier to read) version of the same study can be found at:
http://www.backcountryaccess.com/english/research/documents/FreqDrift.pdf

The important message to winter backcountry travelers is that older avalanche beacons, especially analog ones, may not be capable of having their signals received by the newer digital units.  Older beacons can be returned to the manufacturer to be checked, or if you have access to a newer Pieps DSP beacon it has a feature that can check other beacons for frequency drift:
http://beaconreviews.com/transceivers/Specs_PiepsDSP.asp

Bottom line: if you have an older beacon – such as the Ortovox F1 or M1/M2, the SOS F1-ND, or the Pieps 457 Opti 4 – I strongly urge you to have it checked or consider replacing it.  Extra strong urging if the older beacon has ever been dropped or tumbled.  New beacons aren’t particularly inexpensive, but peace of mind, as they say, is priceless.

Links:
Northern New Mexico avalanche training:
http://www.nnmae.org/edu.html

Backcountryaccess.com learning and education:
http://www.backcountryaccess.com/english/education/learning.php

Backcountryaccess.com research:
http://www.backcountryaccess.com/english/research/index.php

Beacon reviews and information:
http://beaconreviews.com/transceivers/

Recently, my wife and I headed to Colorado for some early fall  hiking.  We spent the day scrambling up Mt. Shivano, a local fourteener near Salida. We summited close to 10am amidst a healthy snow squall: for us, the first snowstorm of the season. But it was rain in the valley below that excited us most.  In our car our ski equipment waited and the steep slopes of the Great Sand Dune National Park were getting soaking wet, hard, and fast.

That evening we traveled to the National Park and watched the sand dunes turn golden yellow from the setting sun just as the rainstorm passed.  We loaded our backpacks with ski equipment and wished we had remembered the headlamps for the evening hike.

Soon enough, the inky blackness of night set in as the storm’s remnants blanketed the moon. The hiking was slow but simple. Even with no moonlight, the lack of trees to navigate, rocks to scramble, and snow to post-hole made climbing up the hard packed ridgeline straightforward.  On either side of us, the dunes slipped away into blackness.  With no landmarks below the pitch seemed to hold endless potential.

We reached what appeared to be the top of a large ridgeline when the full moon slowly emerged and we caught our first glimpse of the terrain below.  Like a silent winter snowscape, the sand appeared soft and pillowly in the milky moonlight.  Like an untracked powder hillside, it beckoned.

With storm clouds threatening to squelch our moonlit shining sand, we sprayed our skis with Armor All for glide, jumped into our ski boots, and pointed them down hill.   With a bit of a running start we kicked down into the inky, cool abyss.  Momentum overwhelmed the sandy friction and we plunged down the dune sliding into the dark.

Soft and deep it was not.  Nonetheless, the hard-packed sand allowed us to gather enough speed to make a solid dozen turns. I came to a grinding halt as the slope petered out and turned to watch my wife lay down “grainy” eights across my tracks. There was nothing artificial about these turns.  Acceleration. Edge.  Sandy grit blew in my face like dry powder.  This was skiing in September.

1. Water and Food

2. Iodine for emergency water purification

3. Matches, lighter and fire tinder ( Cotton Balls or dryer lint soaked in Vaseline stuffed in a film case are super handy if your need to build a fire in the rain )

4. A 50 Gallon Garbage bag can act as a shelter, bivy, poncho etc.

5. Compass , GPS and Map

6. A Whistle

7. Small First Aid Kit

8. Cell Phone

9. Good rain-wear (jacket and pants)

10. Extra Layer.

11. Pocket Knife

12. Headlamp

13. Sunscreen.

14. Wool or Synthetic Hat.

All of these items will fit in a small day pack and if you use small stuff sacks the emergency kit can be kept separate from your accessible personal items. By having them handy you will not neglect to take them even for that quick hike you know so well.

Another major consideration when you head up into the mountains is how you dress. In the outdoor industry we all know that cotton is called the “death fabric” because it absorbs and holds moisture making it lose all insulating value as well as impossible to dry. So you are saying, I hike in cotton all the time and have never gotten stuck? This is lucky and when the day comes for a cotton tail to learn the lesson, they may be lucky to survive hypothermia which can kill the strongest people very quickly. If you are traveling in the mountains synthetic fabrics like Patagonia Capilene® or Icebreaker merino wool can save your life and still keep you warm if they are soaking wet. By packing a few layers , the user will have the ability with just a handful of items to regulate body temperature and survive even the worst summer storm.
When heading out for even the most casual hike be aware of a few items and you can hike successfully in all conditions even a surprise summer snow storm. Tell a friend where you are going, how long you plan to be gone and the route you will be taking. Think Region, Route, Return before you go. Sometime things take a little longer than we may expect so I always calculate a little extra time for my hikes.

Heading intoo the back country even for a casual hike, climb, run or mountain bike can quickly turn into a fight for survival. We encourage you to think before you head out for your next adventure . A few minutes of planning and organizing your pack provides the ounce of security if you get lost or get caught in an unexpected mountain storm. For more information on Hiking safely ina nad around Santa Fe, stop by Sangre de Cristo Mountain Works for the best gear and trail knowledge in the area.