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How Often Should You Update Your Maps?

Hurricane Irene Trail Damage
Hurricane Irene Trail Damage

I was giving a talk about hiking the White Mountain 4000 footers last year and one of the attendees asked me “How often should you update your maps?”

She asked me this question because several major trails in the White Mountains have been closed since Hurricanes Irene and Sandy tore up the  trail system. The rain and flooding they caused washed out many bridges, closed roads, severely eroded some popular trails, and washed others away completely.

I hemmed and hawed about how it probably made sense to update them every 10 years ago, but I’ve been thinking about that question ever since, and I’ve come to a slightly different conclusion:

Plan each hike using as much information as you can,  especially recent local information.

Most of the experienced hikers I know in New Hampshire do this already. We read recent trips reports that are digested by the trailsnh.com search engine or recent AT thru-hiker journals on trailjournals.com if we plan on doing a long section of the Appalachian Trail. Many of us belong to a forum called Views From the Top which is a wealth of local hiking intel and knowhow. We analyze the weather charts available from NOAA.gov and research historical temperature and precipitation information at Weatherspark. And because we’re from the area, we know about all of the trails that are  washed out or were closed by the Forest Service after weather events. Unfortunately the Forest Service doesn’t publish most of these closings online – wish they made it more obvious – and you can sometimes only find the notice at the trailhead.

Compare that to hikers who just plan a hike using a map and a local guide book, even the publications from the Appalachian Mountain Club which are updated every couple of years. They’re out of date as soon as a weather event or an avalanche transforms the White Mountain landscape, a trail crew decides to re-route a historical trail to a more maintainable location, or remove a shelter to re-vegetate an overused area. The 1400+ miles of trail in the White Mountains are extremely dynamic and you simply can’t rely on maps or a guidebook for accurate information.

 So, “How often should you update your maps?” is really the wrong question. We all should asking “What information sources do I need to plan a trip?”


  1. That’s a good point. A related question is how quickly are maps updated after an event like that? You can’t update the maps any more frequently than the upstream data sources do.

  2. I always scour the web for current information for my upcomming hikes. You never know what kind of condition the trail will be in. I have also got into the habit of calling the state parks I will be in (if I am hiking in a state park) to make sure everything is OK.

  3. In the upper midwest, I have noticed that the map carved into the wooden sign board at the trailhead is often more accurate (current?) than the Forest Service map I picked up at the ranger station.

  4. In flying, a pilot is required by law to get a weather briefing before a flight because changed conditions affect safety and it’s awfully hard to pull over at the side of a cloud to wait out a storm. It’s only prudent to get as much up to date information as possible. In some areas I hike, maps haven’t been updated for many years. Online sources, calling state and federal offices who have jurisdiction over the area has helped me many times. I also search for for posted.gpx files of people who have recently made the hike. I found out a trail had been relocated that way.

  5. It did not wash the mountains and valleys away. People need to learn to read terrain on a map and not just follow a marked trail – maps that way have a long shelf life. That way you can navigate off-path, build river crossing skills in and deal with whatever you find. Trail, or no trial. Contour interpretation and the whole detail help you stay located. Not a line denoting a trail giving the illusion you are somehow safe to travel the wilderness on. I like your points. Well said! I will get my coat now.

  6. 1. While planning, use and compare all the online sources that you can find
    2. Learn to *really* read a map, and how to safely bushwhack if the need arises
    3. Always be ready to abandon a hike or route if the conditions you encounter make it unsafe to proceed

    In a pinch, (2) and (3) are all that’s needed. (1) is nice to have.

  7. I’ve never updated my maps, as far as I’m concerned the white mountains in Vineland.

  8. There were a couple of comments about developing the skill to really read a map. I grew up around topo maps and to me, having one is like reading a good book. I’ve taken many a virtual journey just from a topo map. I’ve found numerous new hiking and driving routes that way and on the trail, the ability to “see” the terrain from the map has assisted in many a bushwhack.

    An online source I use often is aerial photography. I do quite a bit of hiking and motorcycle riding in the SW deserts. Many of the maps haven’t been updated for decades. The satellite photos have helped me in route finding when the map doesn’t have current info. I use an Android phone/GPS with downloaded topo maps, imagery, and extra batteries. With all that, I’m never without my paper map and compass.

    Since I own a small sign company and have a wide format printer, I print my own USGS topo maps on Tyvek. Sometimes, I’ll get in my graphics software and stitch maps together when I’m travelling in areas that cross several maps. I also print on both sides of the material.

    • Old maps that haven’t been updated for ages can be more helpful than current ones, especially in the SW deserts. The old quads show wells and tinajas that, more often than not, still contain a liter or two of water today, even though nothing like it is shown on the current maps. I love using outdated maps in remote locations. If I had the choice of hiking the outback of southern Utah with a quad from today or one from 1950, I would pick the latter.

      • Another thing I’ve noticed on many current maps is they are drawing the contour lines from extrapolated digital elevation data. That has a tendency to smooth out the terrain on the map. Smaller detail and gullies get lost and cliffs become just somewhat steeper slopes. The old maps would have contour lines stacked on each other and I rarely see that any more. I do like my old topo quads.

      • I completely agree. Amazing how much detail is lost when they go digital or are updated.

      • I’ve also observed that newer maps sometimes omit sites of archaeological significance or delicate ecology in order to keep the sites from being overused and damaged. The more recent Big Bend National Park maps have excluded a number of springs, trails, back roads, and other places noted on the older copies. I asked a Ranger about it and he said, “We don’t want people to know those things are out there because we are trying to preserve them.”

  9. I am sure many of the people that follow this blog know about this already.

    Christopher Marshall of Amherst, New Hampshire is an avid map enthusiast who started scouring the public libraries of New England for old topos and scanned them into hi-res .tiff images. The University of New Hampshire hosts the collection


  10. Locally I find that the USFS has been leaving Paper Printouts (with maps of trail changes) at the Trailhead advising of any changes which has been very helpful..

  11. If you use old maps, be advised that magnet north is always in flux. Your old map may have a delineation that can be many degrees off after a few decades.

    Check the current difference by sighting the North Star on your compass and noting the degree difference indicated by the needle.

    • In about twenty one thousand years, Thuban will be the pole star and we’ll have to use that to update our magnetic declination. The stuff a prepared hiker has to keep up with is never ending!

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