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I am investigating the feasibility of a hike looping around Hofsjökull. Among the foreseen challenges are 17 crossings of named rivers (and many smaller ones). All rivers I need to cross have 4WD roads fording through downstream from where I will be hiking, sometimes quite far downstream after the confluence of several more rivers. From a driver's perspective, I have seen the recommendation, “if you wouldn't ford it on foot, don't ford it by car”. Logically, it should follow that if a 4WD road does ford a river, it should be fordable on foot (weather permitting). Is this accurate? Can I infer from the observation that a 4WD road has an unbridged river crossing downstream that it may be fordable on foot upstream?

Edit: For the purpose of this question, please assume complete sterility. I am considering only fordability due to water depth and force. I am not interesting in dangers from carnivorous animals in the water.

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    Would you want to ford this on foot youtu.be/6HsdnKJhFsk
    – StrongBad
    Commented Jun 29, 2017 at 1:01
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    @StrongBad Probably not, I might wait for the morning and see if there is a broader spot where it's less deep and/or less flow. It doesn't seem the 4WD crossing goes according to plan either though, so I'm not sure if I would classify this as "fordable by 4WD". In any case I'll hike my loop such that the rivers that seem largest are in the first half of the loop so I reduce the risk of meeting an unfordable river 12 days into a hike. Still, rain can always do that.
    – gerrit
    Commented Jun 29, 2017 at 1:24
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    FYI, you can put your mind totally to rest re snakes. According to Iceland Review, there are no snakes or dangerous spiders in Iceland, mosquitoes are not endemic, but there have been yellow jackets since 1973, found mostly around trashcans and outdoor cafes. I found no mention of crocodiles, but the world's largest crocodile was named after an American of Icelandic descent. The site has a lot to say about flooded rivers and rescuing motorists from them.
    – ab2
    Commented Jul 3, 2017 at 6:16

2 Answers 2

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From The U.S. National Weather Service,

Turn Around Don't Drown®

Each year, more deaths occur due to flooding than from any other thunderstorm related hazard. The Centers for Disease Control and Prevention report that over half of all flood-related drownings occur when a vehicle is driven into hazardous flood water. The next highest percentage of flood-related deaths is due to walking into or near flood waters. People underestimate the force and power of water. Many of the deaths occur in automobiles as they are swept downstream. Of these drownings, many are preventable, but too many people continue to drive around the barriers that warn you the road is flooded. A mere 6 inches of fast-moving flood water can knock over an adult. It takes just 12 inches of rushing water to carry away a small car, while 2 feet of rushing water can carry away most vehicles. It is NEVER safe to drive or walk into flood waters.

I've quoted the warning in full, and bolded the part that sheds light on the OP's question. The bolded sentence says to me that fordable by 4WD vehicle does not necessarily mean fordable by foot, even upstream of the ford. (Note: 12 inches equals one foot equals 30.48 cm.)

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    Furthermore, how wild a river you can ford dramatically decreases if you're not using any of the good techniques that exist for it or if you're trying to use one you've never practiced. Meanwhile the wildness of a river you think you can ford dramatically increases under the same conditions. Fording rivers is one of those things you do not want to learn from a book or off a website. It's not hard to learn, but you do need to learn before trying it alone in the wild.
    – Monster
    Commented Jul 8, 2017 at 17:21
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The presence of a ford in a river is a local condition: it's a point in the flow where the river has leveled out, producing a wide, slow, shallow flow. In addition, a ford generally has a hard bottom, either naturally or through "improvement" with imported gravel. The presence of a ford at one point says absolutely nothing about the fordability of that river anywhere else.

In answer to your secondary question, "you can ford it here by car" does strongly imply "you can ford it here on foot".

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  • I am surprised by your statement, * The presence of a ford at one point says absolutely nothing about the fordability of that river anywhere else*. Upstream of several confluences, a river should contain substantially less water. All other things being equal, that should make the presence of suitable fords (far) more likely, shouldn't it?
    – gerrit
    Commented Jun 29, 2017 at 10:12
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    I guess the answer to your exact question (comment) is yes, but the problem is the requirement "All other things being equal". Upstream it can be narrower, steeper, treacherous ground, ... that make it unfordable even though there is less total water.
    – imsodin
    Commented Jun 29, 2017 at 11:27
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    @gerrit, "All other things being equal", yes, but with rivers, things are almost never equal. For example, fording the St. Joe River just upstream of Bacon Creek is easy (if a bit deep for my taste), but just a few hundred meters further upstream, the valley narrows, and it's three kilometers (and a number of tributaries branching off) before you find another good ford.
    – Mark
    Commented Jun 29, 2017 at 22:02
  • @Mark True. I'm not worried about 3 km, though. But if you can ford here by car does imply you can ford here on foot, then in the worst case I only have to follow the river at most 14 km downstream to ford where the cars are supposed to. Chances are I can ford it earlier. A 20 km detour is not a big deal, but having to turn around and backtrack to the beginning 12 days into a two week hike is problematic.
    – gerrit
    Commented Jun 29, 2017 at 22:52

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