Ski Group Leader: These checks work best if one person leads the group through the check. In a guided group this is usually the guide, in non-guided groups this is either one of the more experienced members or a person designated by the group. Designating a leader is generally a good idea, even in very experienced groups, as it can help ensure that someone is responsible for making sure that no critical details are overlooked at the start of the ski day. Accidents are more common in groups of experienced back country skiers, one common cause being "leaderless" groups, where each member incorrectly assumes that someone is keeping an eye on the big picture. The leaderless group is often the result of a bunch of nice folks not wanting to step on each other's toes.
Avalanche Beacon Battery Check: Entire group turns on their beacons and confirms that battery power is adequate for beacon type and for length of use. On BCA Trackers, the manufacturer's specs say that battery power must be "greater than zero," I prefer people to have 50% or greater battery power. On my Barryvox beacon the battery power needs to be 70% or greater. At this step you should also confirm that each group member has a spare set of batteries for their beacon. Also make sure that nobody is using lithium batteries as they can lead to problems with digital beacons transmitting properly. This is related to voltage and too complicated to explain here, the take home point being don't use lithium batteries with digital beacons.
Avalanche Beacon Search Check: Entire group turns beacons to search, and turns sensitivity or volume down as far as possible, while leader's beacon remains "off." Once everyone is set to search (no beacons should be making noise at this point), leader turns beacon on and leaves in transmit (send) position. Leader then checks each person's beacon to make sure that it is receiving the signal put out by the leader's beacon.
Avalanche Beacon Transmit Check: Entire group switches beacons to send (transmit) and secures them for travel. I generally define secure as in the the beacon's harness and under at least one layer of clothing, or in a securely zipped pants pocket. Note that the pocket method is a bit riskier as zipped pockets can be left unzipped and the beacon is more susceptible to be being damaged in a traumatic event such as an avalanche. Best to wear your beacon in it's harness if possible. The leader now switches their beacon to receive and slowly checks each member of the group as they walk past the leader. I turn my beacon all the way down and dedicate a good 5 seconds to each person to confirm that I am in fact hearing their specific beacon. Once the last person reaches the leader, they should have the leader switch to transmit and watch them stow their beacon securely.
Beacon Function Test: These three checks: battery, search, and transmit, constitute the beacon function test. This should be done at the start of every backcountry ski day, no matter what. We will next cover the range check, which should be done at the start of the season and at the start of extended trips.
Avalanche Beacon Range Check: Start by designating one leader and having everyone else get in line, shoulder to shoulder, facing the leader. The leader then turns their beacon off and walks approximately 100 meters away from the group. Everyone in the group switches their beacons to search (receive). The leader then turns on his/her beacon and walks slowly toward the group. Each group member notes the point at which their beacon picks up the leaders beacon. This is the "search range" of the member's beacon. Once all beacons have picked up the leader's beacon the entire group switches to transmit, and the leader once again turns their beacon off and walks to the spot 100 meters from the group. Now repeat the process, but this time have the leader turn their beacon to search (receive) and have each person walk toward the leader until the leader picks up their beacon, note this distance, it is the "transmit range" (send range) of the member's beacon. The member now turns off their beacon and walks back to the group, replaced by the next member.
Note on Signal Drag: Ever noticed how you can leave a city with your car radio on a favorite channel and your radio will hold that channel until you switch channels, at which point it is hard to get it back? This is called "signal drag" and it is the reason we have the leader get completely out of range when starting a properly run range test. If the leader starts with the group with their beacon on and walks away, the range distances can appear to be much greater due to this phenomena of "signal drag." By walking into range, you get a more realistic reading, which is the situation you will more often find yourself in during an actual avalanche rescue scenario.
One bonus of doing a function and range test in any group is that you quickly can see that everyone knows how to turn their beacon on, toggle between search and transmit, and stow their beacon. In an experienced group, it is often difficult for people to mention their lack of knowledge and these sort of activities can serve as a good review without pressuring anyone.
You may want to mix things up for speed. We often start with a battery check, do the range tests, and then finish with a transmit check where we confirm that everyone is transmitting and has stowed their beacon properly. All beacon checks leading to touring need to end with the transmit check and confirmation that the beacon is securely stowed.
Don't forget to start every season with some practice at companion rescue, including beacon searches and rescue digging, and do a function and range test on your first tour. Even professionals find that these skills get rusty over the summer. There is nothing wrong with taking the same Level 1 Avalanche Course multiple times, particularly if you do not backcountry ski often enough each winter to retain the knowledge from year to year. Repetition of training is what allows us all to perform in the real situation as it allows us to fall into a familiar pattern in what is often a stressful situation. A full range and function test at least puts to rest any concerns about group member's beacons working properly on a given day or trip and is an essential ski for participation in something like the Verbier Haute Route or Ortler Ski Circuit.
Note on terms used in this article. The terms transmit and send mean the same thing, the terms receive and search mean the same thing. I used them interchangeably here so that you could become familiar with each term. I find that transmit and receive flow more naturally from my lips, but send and search seem to be favored by current AIARE Level 1 providers.
Opportunities to learn the Beacon Function and Range Checks with an AMGA certified Ski Guide include the following Northwest Mountain School backcountry ski training programs: AIARE Level 1 Avalanche Course, Introduction to Alpine Touring (AT) Course, and our Avalanche Beacon Clinics at Stevens Pass Ski Area.