How To Navigate Using a Map, Compass, And Altimeter
It felt like a stroke of luck when, after hours traveling through a whiteout on Mount Baker, we finally popped out from underneath the clouds and we could actually see our camp. Then again, we had diligently followed a route plan I had sketched out the night before and updated during the ascent. Thanks to the plan, we were back to the comfort of our tents, in spite of several disorienting hours in a total whiteout on the glacier. So, we’ll compromise and say luck favors the prepared.
To create and use a route plan, you will need a small weatherproof notepad, a sturdy pencil, a compass, a topographical map and an altimeter. I will assume that you are already familiar with these tools. If not, you will need to become comfortable with maps, compasses and altimeters before you can learn how to navigate.
- Learning to use a map and a compass are basic steps in improving your navigational skills. Photo by Wade Trenbeath.
Getting Started
The first step in formulating a route plan involves studying the map and sketching out the route. Separate your trip into many “legs.” A leg is simply one section of the route. For example, Leg One could be from camp to the rocky ridge, Leg Two could be from the rocky ridge to the toe of the glacier, Leg Three could be from the toe of the glacier to the flat area of glacier at 9,000 feet. Keep each leg as short as reasonably practical to minimize your chances of making an error while traveling through that leg.
Using your compass, determine the bearing that you should travel to reach the start of the next leg—write down the bearing for both the ascent and the descent, and write down the start and ending elevation of each leg. I find it helpful to draw the lines and bearings on the map, in addition to recording the information in my notepad.
Hiking Handrails
Try to incorporate “handrails” into your route plan. For example, in Leg One, it would be intuitive to simply aim directly for the base of the rocky ridge. However, in a whiteout you could follow a bearing of 40 degrees towards the base of the ridge and walk right past it without seeing it. A better plan would be to aim a few degrees off, say around 43 degrees, and try to hit the middle of the ridge so that you can’t miss it. Then you can follow the ridge, using it as a “handrail.” Use handrails whenever possible—this minimizes time spent navigating using instruments, minimizing your chances of making an error. When traveling, save time by folding your map so that your entire route is visible, and place the map in a zip-locked bag so that you can see your route. Keep the map in your pocket and check it frequently.
Importance Of Using A Map
Using your map, identify areas where disorientation is likely in a whiteout, such as large flat sections of the glacier. You might consider using “wands” along these sections. Surveyor’s flags work just fine for this purpose. Place a wand every ropelength when in doubt, or more in a heavily crevassed zone where finding the exact way down is critical. Don’t rely on wands placed by others; they may not be there on your return.
If there is a break in the clouds, take advantage of it by orienting yourself on the map and taking a bearing to your next destination. Using your altimeter, you can further define your location on the map by triangulating bearings and taking a reading from the altimeter and seeing how it corresponds with the map. Be aware that elevations given on the map for a glacier are not totally reliable since the features on a glacier change. Also, your altimeter needs to be recalibrated frequently. Recalibration should be done in a location where there is a known elevation. Altimeters work using barometric pressure, and changes in barometric pressure change the reading of the barometer.
If the question “Can’t I just use my GPS?” is running through your head, remember that their batteries can fail. GPS units can greatly simplify the problem of determining location in a whiteout, but the GPS is a tool to be used in addition to the core navigation tools of map, compass and altimeter.
The next time bad weather ruins your weekend plans, use the time to head out to the mountains, find an area that is relatively safe and where you will not get lost, and practice your navigation skills. If you’re lucky, it’s a skill that you will never have to rely upon—but when you do find yourself stuck on a glacier in a whiteout, you’ll be happy you took the time to learn how to navigate.
Todd Miller is a professional mountain guide based in Seattle.
Document Actions
- Email this page
- Print this
- Share
