2

Conditions:

  1. I live near a wide (~1000ft or 300m) and fairly deep river across from the area where I work.
  2. This area is slightly earthquake prone -- near a fault line that has had multiple magnitude 7+ earthquakes.
  3. While there is a bridge nearby, if that bridge were to collapse, the next bridge is another 14 miles (23 km) away... the one after that is another 30 miles (48 km).
  4. The area is a major city region, often with clogged highways even in good weather, and no disasters.
  5. There are probably close to 100,000 people who commute over this river.

If a large earthquake were to hit again, it could take out my local bridge. Assuming that I am escaping on foot, reaching the next bridge is a significant trek. I live less than 2 miles from this river, so it's the shortest way home (by far). There are no ferries in this area, either.

In the scenario where I have to rush home to my family after a disaster, what is the best way to cross the river in winter (note: the river rarely freezes, but it is often around 32 F / 0 C in the winter)? Is the risk too great to try to cross the river (i.e. risk hypothermia from full submersion)?

A related topic is here: River crossing in winter?

In this related topic, it mentions about how to handle your feet, but not your clothes. Do I strip down and bag the clothes? Do I invest in a lightweight blow-up raft and telescoping paddle? Do I get a cold water wetsuit?

Something I considered is that if I travelled far enough outside of the city, I could probably hitch a ride, but the traffic might be terrible, or the bridges (if still standing) might be closed due to damage or rubble, thus rerouting traffic very far around (and ultimately away from my home and family).

A helpful table (source): water temperature survival time

Update:

The river flows at an average surface rate of 2.5 mph (4 kph) -- a little slower than walking speed. The gage height varies greatly. As low as 7 ft (2.2 m) and as high as over 30 ft (9.2 m) during heavy periods of rain. The yearly average appears to be around 17 ft (5.2 m). Temperature data puts it between 10 C and 1 C during the winter months (occasionally with surface freezing).

I don't need to enter the river. I need to overcome the river in a very rare emergency situation, ONLY. How do I reduce my risk and minimize the time to get to the other side of the river? I assume that nearly all solutions will require "hours", but I want to avoid "days" (i.e. waiting for the national guard to setup travel routes and clear the roads).

  • The °C temperatures in that table seem very precise! – Toby Speight Jan 22 at 10:00
  • 5
    Do you have a really really good reason for crossing the river? Because the best solution is to not cross the river. – Separatrix Jan 22 at 11:51
  • @Separatrix It would only be in an emergency+disaster situation, due to the local fault line. I'm slowly developing evacuation routes and backup plans for local disasters. The local bridges have been remade in the last 10 years (roughly), so they should be up-to-code. I doubt they would fail, but I realized that I have no plan of action if they do. In a big earthquake, emergency crews are overwhelmed, and most of my family lives across the river. I'm just looking for possible solutions, or work-arounds, to a difficult situation. – Cryptc Jan 22 at 13:14
  • 3
    What you probably need is separate escape plans for each side of the river and a rendezvous point away from the likely affected zone. Crossing the river remains a bad choice until you're away from any affected infrastructure. – Separatrix Jan 22 at 13:48
  • 1
    One of the cardinal rules of rescue is to not put yourself in danger needlessly. The idea of crossing a wide river in winter temperatures during a natural emergency fails this on so many levels that it's weird you would even consider it. How would you react if you were then in distress from your own doing and so caused another rescuer to die trying to rescue you? This is frankly irresponsible. – Gabriel C. Jan 23 at 19:48
6

From how it sounds, the river is too deep to walk through. I strongly advise against trying to swim through it in winter - if you are not well trained, well equipped and know the river very well, this is very likely deadly.

Also, I advise against using some makeshift equipment or a blow-up raft. The river will likely become deadly after an earthquake strong enough to take your bridge out, even if it is slow and peaceful during normal times. This is due to possible waves during aftershocks, but mostly because of rubble and other things swimming downstream. There might also be a broken power line or underground power cable, maybe even running through the bridge you mentioned, submerged in the river. Furthermore, you don't know how the riverbed might have changed due to debris or the quake, which could lead to very dangerous currents.

Since the question is very general and broad, I would suggest to stick to what the authorities ask you to do in that case. The last thing disaster control wants to take care of in that situation is the guy who thought it would be a good day to try to swim through the river.

  • So, you're saying, think of it from a civil engineering perspective. Do you know what the authorities might do in such a case? I see your point about the river being a deathtrap, but "wait and do nothing" could be difficult if your family is at home and part of the house collapsed. In that case, time is life, and the river saves time (at great cost). So, instead, wait for the national guard to create an evacuation route? Steal a dirt bike? Stash a paramotor? Invent Star Trek teleportation? That river becomes one giant, stretching barrier. – Cryptc Jan 22 at 2:17
  • @Cryptc The answer will depend on your specific location. From the information you gave, I can only give the general advice that I gave. I don't know what the authorities might do in such a case - in my country there are authorities which will likely set up a makeshift ferry service as soon as possible, but that might take a while. But you can ask your authorities about their plan for such a situation in advance - makes more sense to me than buying an inflatable raft. You will be no help to your family if you die in that river. – Paul Paulsen Jan 22 at 7:11
  • But of course it depends on the river, it might not be that difficult to cross it. Maybe somebody else has a good idea. – Paul Paulsen Jan 22 at 7:13
  • I pulled up some numbers for my area. The river flows at an average surface rate of 2.5 mph (4 kph) -- a little slower than walking speed. The gage height varies greatly. As low as 7 ft (2.2 m) and as high as over 30 ft (9.2 m) during heavy periods of rain. The yearly average appears to be around 17 ft (5.2 m). Temperature data puts it between 10 C and 1 C during the winter months (occasionally with surface freezing). – Cryptc Jan 22 at 12:56
  • @Cryptc that is good information. I will think about it, maybe something comes to my mind. You should add that information to your question though, it will help others trying to answer. I still think that asking the authorities for their plan is good, then you get a better idea of how the situation might look like. And I think disaster back-up plans are not exactly the expertise of this site, so you might get better answers elsewhere. – Paul Paulsen Jan 22 at 14:53
2

Regardless of the water temperature, trying to swim across a river after an earthquake that brought down a bridge is a probably not a good choice. Underground septic and sewer systems will be damaged, likely contaminating the river for hours to days. Commercial storage facilities for fuel and chemicals are will potentially also contaminate the river water. Drinking Water & Septic Systems after earthquake (PDF)

Per your question, you are in developed area, with a navigable river. In the winter the water is near freezing but seldom frozen. Per your self-answer money is not a significant hurdle for arranging the crossing. You have listed a moderately swift current 2.5 mph (4 kph) which likely implies there are no dams on the river (i.e. loss of dam during the disaster is not a consideration)

In the natural disaster that brings down a bridge, local communications will likely be disrupted. It will be difficult to know if other bridges are still functional, so attempting an overland journey on foot to one of them is not practical in the first few hours.

  • Depend on the greed of your fellow city dwellers who own boats. A river that size would be expected to have many boats. Some of those boat owners are going to realize a water taxi is a great idea, particularly if more then one bridge is down.

  • Go the other way by car. Drive away from the city center by the easiest route. When you are past the area of high impact (no significant damage) take the long way home. At 50 miles from the epicenter of the quake normal travel speeds should be expected. If you drove East 50 miles leaving the city, drive north 50 miles, drive west 100 miles (crossing the river), drive east less than 50 mile to get home.

  • Keep a bicycle at work, used bikes are inexpensive. On good ground you can make good speed, on bad ground you can easily carry it. In congested areas you still make good speed. 7 miles per hour is an easy speed to maintain, so a bridge 30 miles away is an easy 4 or 5 hour ride. If you bike regularly, speeds of 20 miles per hour plus are reasonable, you potentially get home in 4 hours.

Also keep in mind, in an urban/city environment where there is no power and/or communications (cell service is likely out as well), all payments need to be cash, ATM's don't work, credit & debit cards can not be validated or charged.

1

Here are the ideas I've come up with so far...

Reasonable:

  1. Pay for a helicopter emergency service to go directly to the house.
  2. Have an emergency GPS beacon at home to alert a variety of emergency services to my family's exact location, if trapped--assumes the phone lines are either down or overwhelmed.
  3. Join a neighborhood safety organization to get local families to check on one another in the event of a disaster, expediting help.

Less reasonable:

  1. Stash a paramotor (to fly home) at a safe location.
  2. Stash a dirt bike (to weave through traffic or go off-road) at a safe location.
  3. Stash a Sea-Doo at a safe location (how will I get it to the water w/o a vehicle?).
  4. Get far enough outside the disaster zone to catch a ride and pay them to go the long way around (over a working bridge), to a point where I could walk the rest of the way (many unknowns and might still take a very long time).

Incredibly dangerous (and stupid):

  1. Keep an inflatable boat and oar in the trunk.
  2. Keep a cold weather wetsuit in the trunk.
  3. Parkour over the metal bridge spans (which are taller than the water is deep).
  4. Keep and use a rope to span the broken part of the bridge.

Note: Every solution is situational. Each solution has upsides and downsides depending on the exact circumstances of the emergency, the availability of help, the condition of infrastructure, the amount of time available, and cost/training/feasibility.

Please poke holes in these ideas.

  • Actually the motorbike isn't a bad call if you need to get anywhere after a disaster, it needn't be a dirt bike, you can just start commuting on an "adventure" bike. – Separatrix Jan 24 at 8:40
  • This contains some good idea. I think the neighbourhood organisation is a very good one. It is unlikely though that a GPS beacon will work in a collapsed building. – Paul Paulsen Jan 24 at 10:07
  • Keeping an inflatable rubber dinghy (+/- 2m long) and 4HP outboard engine in your trunk would actually be safe for such a crossing. (but still a large investment for a very unlikely event) – HTDutchy Jan 24 at 11:01
  • 1
    Reasonable #3 is the best. I'm curious if you are still considering swimming the river if it's not winter? – topshot Jan 24 at 16:49
-1

The tables above are generalizations. "Your mileage may vary" But the numbers to me do not look like extended effort numbers, but huddle and try to remain conscious numbers. Swimming results is lower numbers due to fresh cold water passing the sides of your torso and groin.

I suggest you do a controlled experiment.

Experiment 1:

In a public pool swim laps equal to the width of the river times some safety factor. I would suggest 2. Tow your gear in a dry bag. Record your time.

Experiment 2:

Do this with a line attached, a friend on shore at the other end of the line, and suitable warm car or fire nearby.

Start well upstream of your parking point, unless you are a very strong swimmer.

Swim in the river parallel to the shore for a time equal to experiment 1. Get out, open your drybag, dress, and walk two miles.

My suspicion is that you will find that it's not a good idea.

At summer camp we had a pair of twins that could do a mile swimming in 22 minutes, which implies 1000 feet in under 5. They were skinny like rakes. They were also state champions.

Bronze medallion, a common standard for swimming for supervising water related programs requires 500 yards in 15 minutes. By extension that is a mile is 50 minutes or just over a mile an hour. You are going to be in a stream that you say has a significantly faster flow than this. Which means even given laminar flow, you would go downstream about 2.5 times the width -- half a mile -- while crossing 1000 feet, assuming that you kept at right angles to the shore.

Me: I would consider doing this as a bet with a safety boat during the summer when the water temps are above 21 C (70 F) as I know from experience I can spend an hour in such water and only be very cold. I would not attempt it in winter except to escape a pack of Zombies.

Story time:

I had a group of kids in voyageur canoes on the Athabasca River in September. The week before had been cool and wet, and the rain on the Athabasca icefield raised the river to flood levels. The glacier only being about 60 km upstream chilled the river to somewhere between 3 and 5 degrees C.

Partway through the first day my canoe dumped in a class I rapid.

Another canoe got a line to us, and attempted to tow us to shore. Everytime they would get into slower water we would pass them and drag them out. Finally, with a doubled line and them going the full length downstream before attempting to get to shore we were successful.

All the kids still had enough coordination and strength to hold on to the gunwale throughout this, but we were in the water for about half an hour.

The third canoe in the group went to shore and started a fire once it was clear this attempt would work. We got the kids to walk down to the fire, and got everyone out of cold wet clothes. This was not trivial. Fingers were cold enough that we couldn't feel the buttons or zipper tabs. had a hard time gripping fabric.

One thin boy was cold enough to be irrational. we had to sit him on a log and one person stood behind him with hands on his shoulders to keep him from walking into the fire.


Point of this story: These were kids who moved minimally while in cold water, were wearing wool mackinaws or sweaters, were in water several degrees warmer than your winter river will be. Once on shore they were barely functional.

You still have to dress yourself on the far side of the river. Your fingers won't do what you tell them. Your feet will be numb. You won't be able to feel what you are walking on, nor feel injury to your feet.

Things like this take preparation. If you seriously want to do this, try it in summer first. The first time you do it, do it with a life jacket on. My experience with the North Saskatchewan, a river with similar current, but narrower width is there is significant turbulence that will pull you down at unexpected moments.

Alternatives.

  • Canoe. Keep a cheap canoe at work. For this use a coleman pipe frame canoe is fine.
  • Inflatable boat. Likely more expensive than the canoe, and you can't count on it being intact after years of storage.

In either of these cases, practicing is essential. You need to be reasonably proficient with using them in normal temps to have a prayer of using them under adverse circumstances.

  • Bicycle. A bike can get through when cars are jammed up. A 14 mile detour = 28 miles = 2+ hours. Even if you have to go 2 bridges down, you will get home in about 1/3 the time it would take to walk, certainly within 24 hours.
  • Moped. Bike with a tiny engine to augment your efforts. Call it 1/2 to 2/3 the time of a bike.
  • Small scooter. The ones you see all over the orient used as commuter vehicles. Faster than a moped, and a lot less effort.

Again: Practice. Commute at least once a month this way so you can find out it's and your limits. What's it like biking in a cold winter rain?


A comment points out that earthquakes severe enough to take down bridges may also take out sewer lines. I've no idea how fast the river would become contaminated. With a 2.5 mph flow, I would expect it to be fairly dilute, unless you have extensive civilization upstream.

  • I don't think this is a good answer to the question. Your are suggesting the OP swim across a river after an earthquake sufficient to bring down a bridge. Which is also going to break sewer lines contaminating the water, as well as adding who know what kinds of debris. – James Jenkins Feb 10 at 10:14
  • I will admit that broken sewer lines hadn't occurred to me. I think the tenor of my answer, however, was to give him a procedure for testing this idea without dying. I will edit my answer to make this clear. – Sherwood Botsford Feb 11 at 13:39
  • The water is described as being close to freezing. Experiment 0: find a large container of icewater. Dive in. See if you go into shock. Swimming in cold water is very different from swimming in your local pool. – Mark Feb 13 at 3:54

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.