Not bear- or idiot-proof: Documented canister failures

The Bear Vault BV500, which offers good volume for its weight at a reasonable price

At least most of the time, hard-sided canisters like the BearVault BV500 successfully protect food from bears and “mini-bears” in the backcountry. But it turns out that they’re not 100 percent bear- or idiot-proof.

Recently, I received a spreadsheet that documented 199 food-related bear incidents with backpackers in Yosemite National Park between July 2012 and July 2017. The actual number of incidents in Yosemite and the larger High Sierra is probably greater (maybe much greater), because many incidents are not reported and because black bears inhabit most corners of this world-class wilderness.

The sheet describes multiple failures of “approved” canisters from Bearikade, BearVault, Garcia, and Lighter1, due to both human error and design/structural flaws, as well as of early Ursack models. It also provides anecdotal support for Yosemite’s food storage regulations — for every one bear canister failure, there are several cases of bears obtaining food or scented items that were:

  • Kept inside of an unattended backpack or shelter;
  • Hung in tree;
  • Buried; or,
  • Left out overnight unprotected.

These storage “techniques” may work elsewhere, but not in Yosemite, which is home to arguably the best trained camp robbers in North America.

Geographical concentration

One striking takeaway from the spreadsheet was the geographical concentration of the incidents. Of the 199 reports, 142 (71 percent) happened in just four places:

  • Snow Creek,
  • Little Yosemite Valley (LYV),
  • John Muir Trail (JMT) above LYV, and
  • Lyell Canyon, the main trail through which is the JMT.

While it’s reasonable to expect more incidents in high-use backcountry areas (i.e. more backpackers = more incidents), the frequency still seems disproportionate — I’m doubtful that on any given night, three-fourths of all backpackers in Yosemite are camped in just these four locations.

These epicenters make a strong case for selecting campsites more deliberately and avoiding high-use spots and corridors. Like a berry patch in August, bears have learned that some sites are reliable sources of calories.

I think it’s also worth mentioning that these four areas tend to attract many first-time and beginner backpackers, who generally will not be as educated in backcountry matters like proper food storage and bear behavior. I wonder if the frequency of bear incidents is exacerbated by the lower average skill level of this demographic.

Lyell Canyon, one of four epicenters of bear activity in Yosemite


Bear canisters are more vulnerable to failure than I thought, mostly due to human error. The incidents fall into five buckets:

1. Overflow

July 31, 2012. Troop of boy scouts couldn’t fit all their food into their 14 bear canisters, so they hung two stuff sacks with food from a tree. The bear climbed the tree and dragged the food down and ate it. There was approximately 5 to 10 pounds of food. Troop leader got a mandatory appearance citation.

For a canister to do its job, all food and scented items (e.g. toothpaste, sunscreen) must be stored inside, not just most of it. This can be a challenge at the start of long trips, because the typical capacity of a full-size canister is about 6 days of food, plus/minus depending on your daily caloric intake and your food’s spatial and caloric density (e.g. bagels versus Snickers, canned soup versus dried soup mix).

But, understandably, you may be reluctant to carry two canisters, at double the weight and cumbersomeness. In that case, what are your options? Until all of your food and scented items can fit in one canister, consider:

1. Staying in established backcountry campsites with permanent food lockers. In Yosemite, find them in Little Yosemite Valley and at High Sierra campgrounds like Glen Aulin. In Sequoia-Kings, refer to this map of locations.

2. Camping in areas where non-canister storage methods (e.g. Ursack Major, hanging) are permitted. Canisters are required throughout Yosemite but only in the highest-use areas of Sequoia-Kings and the National Forests (e.g. Mt. Whitney Zone in Inyo). In lower-use areas, there tends to be less bear activity.

Last summer I yo-yo’d the Pfiffner Traverse in 9 days, starting at Berthoud Pass. By the time I reached Rocky Mountain National Park, where canisters are required, I was able to fit all of my food inside the canister. In the James Peak and Indian Peaks Wilderness, I used other accepted methods to store my food at night.

2. Unlocked

July 20, 2012. A bear came into the campsite and broke into an improperly closed carbon fiber canister. The bear was able to eat a bag of trail mix before it was scared away. Initial verbal yells and rocks did not phase the bear. After screaming loudly the bear ran away. The visitor was contacted and disclosed that only one of three clasps on the canister were latched properly. The bear pried the top off and sheared the single closed clasp to obtain the food. The canister was not smashed.

July 25, 2013. The bear canister was screwed closed but not past the locks on the lid. The canister was opened but not broken. The bear clawed through plastic bags and obtained food. Food eaten includes pancake mix, salami, power bars, Gu gel, crackers, and nuts.

This would seem like an obvious one, but there were at least 10 cases of bears getting into unlocked canisters. Bears are smart and persistent, and have exceptionally strong and dexterous claws. Due to past successes, they will attempt to twist off the tops of BearVaults and pry off the tops of Bearikades and Garcias.

The solution to unlocked canisters is easy: lock them! Establish the double-checking of canisters as part of your nightly routine, along with brushing your teeth and emptying your bladder. In some groups, it may be worth assigning a canister tsar who oversees this responsibility.

3. Open

August 29, 20152 bear cans in camp, one was closed the other was open. Hikers were cooking soup. Bear walked up behind a log and stood up on its hind legs to peer at the hikers cooking soup. Hikers yelled and stood up and grabbed poles to bang together. Hikers became scared and thought the bear was becoming aggressive so they backed away from their open canister. Bear approached canister, grabbed it by its opening, and walked away. Canister was unrecovered. Bear obtained trail mix, bars, and medications from a first aid kit.

Some bears in Yosemite exhibit remarkably brazen behavior, because they have been “trained” to, i.e. brazen behavior = food. Sometimes they get shot with rubber bullets by rangers and hit by rock-throwing backpackers when they get too close, but they also encounter scared individuals and groups who “sacrifice” their canister for the sake of personal safety.

That reaction is understandable, but it does not help the backpacker or the bear. If your canister is open, never be more than a step away. And if a bear enters camp, immediately lock your canisters and then start throwing things at it (e.g. rocks, sticks, sugar pine cones), aiming for non-face areas. In bear language, this defensive behavior says, “Go away. There are easier calories elsewhere.”

4. Rolled away

June 2, 2015Campers at Snow Creek bridge had bear canister taken. Second time in 2 years at the same area. Could not find canister in surrounding area. No evidence of bear. Model of container is Bear Vault 450.

June 5, 2015Two bear canisters were rolled into Snow Creek overnight. Even after taking all precautions. Also the bear chewed on some camping gear like our table cloth and plastic bag probably due to tiny amounts of food residue.

No less than 30 canisters went “missing” after a bear rolled it away in the middle of the night. This was exceptionally common along Snow Creek — canisters get rolled into the creek (which has enough volume in late-spring/early-summer to carry away a canister) or off the nearby cliffs.

The park recommends storing canisters outside of camp, for safety reasons. But pick the spot wisely. Personally, I keep my canister about 20 feet away and leave my (clean) cookpot on top, so that I would be woken up by the commotion.

5. Structural failure

August 3, 2012. Bear got food from IGBC approved “” brand canister by breaking the hardware that keeps the lid on. The visitor reported the bear at 2300 and described it as being “black”. The bear got the complete contents of the container including: 2.5 bags of mixed nuts, half a salami, 2 bags of triscuits, 6 “Zoneperfect” bars, half a bag of vita-light juice mix.

July 18, 2013. Bear took rental Garcia canister out of a spot in the bushes around 1:40am. I got out and chased the bear away. I placed the canister deeper in the bushes. We were awake for another hour-hour and a half. We didn’t hear it again, but in the morning it was gone. On our hike out we found the empty and broken canister without lid about half way down the [Snow Creek Trail] switchbacks.

July 31, 2013. A JMT hiker decided to use an Ursack [pre-S.29 AllWhite version, now Ursack Major] for most of the JMT because, “it was much lighter and pack friendly.” The visitor understood that, “it was not approved for parks like Yosemite because the food could be obtained by the bears by chewing on the fabric even if they didn’t tear it open.” When she got to Yosemite she, “signed up for a free bear canister loan program, but kept her Ursack in case of overflow items.” She and her friend woke up in the night to scratching and saw a sow with cub, “trying to get into her food bag 80 ft. away. They shouted, shone lights, and threw rocks.” By ’30 minutes’ into the encounter, “the bears had a hole in the side of the ‘bear proof’ bag.” Eventually those bears moved on, but before the night was out, two more bears had stopped by to eat the food and garbage still left. The visitor was left with, “a demolished Ursack and a whole lot of slobbery bear smelling mush.”

August 10, 2014. Bear juggled and threw bear canister until it popped open. Bear consumed all contents: oatmeal, rice, shot blocks, cliff bars.

When used properly, only a few canisters flat-out failed. In most cases, they were smashed open after being rolled off a cliff, usually along — you guessed it! — Snow Creek.

It would be helpful to know the brand of the broken canister, but the spreadsheet did not always specify it or include sufficient clues (e.g. “carbon fiber” = Bearikade). From what I can gather, when used properly there were no reported cases of broken Bearikades or the Ursack Major (formerly S.29 AllWhite), and only one BearVault. The Garcia canister failed most often, but you’d expect that since they are the most common rental canister.

Questions about bear canister best practices? Have an experience to share? Leave a comment.

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