Introduction: Snow Arch

Picture of Snow Arch

After reading about Brunelleschi's Dome, my brother and I had an goal to build an arch out of snow. It doesn't follow his stone chain method, but it is a free standing arch.

Things you'll need,
- Snow of the right consistency. Not too dry, not too wet. Packable.
- Cool temperatures. This arch was built in warm temperature, which led to its short life of about an hour.
- Support braces. We used a series of sawhorses, boards, and snow.
- Ladder
- Block mold. We used kitty litter buckets. It should have flat sides and have a slight taper.
- Some sort of scrapping tool.

Snow Arch from Paul Maiorana on Vimeo.

Step 1: Foundation

Picture of Foundation

Find a flat surface and clear an area about 3'x3' down to the ground. For our arch we had a distance of about 14' from center of support to center of support. As you can see from the picture, I used an ice scrapper to measure an equal distance from a point we wanted as center. Also notice we used a larger form for the first two rows of the arch.

Step 2: Stack and Fix

Picture of Stack and Fix

As you begin filling your forms and making your blocks, try and make them as compact as possible. Any weak areas of the block will eventually make your arch shift, trust me. Let the natural taper of your form begin to slowly form an arch. Do this by stacking every block with the small side of the taper towards the center of the arch. You will see it slowly bend towards the middle.

As the arch builds it's important to step back and adjust the pillars. It's snow, so it will shift and compact. Make sure you help the snow pillars get back to a true state, perfectly straight up and down from left to right. Obviously, keep the arch arching, but the front to back may need to be straightened.

Step 3: Build and Support

Picture of Build and Support

Now the fun starts... Keep forming blocks and keep stacking. Keep adjusting front to back and keep stepping back to make sure both sides are arching in with the same degree and curve. As the pillars grow in, they will need support. You want to keep this as simple but as strong as possible. We used sawhorses with a simple board for the first layer. We supplemented smaller supports by using blocks of snow that didn't make the cut for the arch. Make sure you support the natural arch of the snow, do not over support it by pushing the curve up.

Step 4: Keep Stacking

Picture of Keep Stacking

Keep stacking and adjusting from front to back. Make sure both pillars take the same shape and are working towards aligning at the top. As you keep staking, add another board for support. Then more snow supports then another board as you see if. This will vary depending on the size of your arch.

Also, you can see that we've added some front to back supports. Our blocks were very wet and heavy and compressed a great deal, which led to some serious front to back movement. We added some front and back buttresses to add support. We needed this to make this thing stand. You may need it too.

Be careful of hoop stress. Hoop stress is the outward force the arch sends due to the vertical weight on the curve. The goal is the properly direct all this stress into the ground. Do this by keep a smooth curve from the bottom of the curve to the top. If you have vertical sides on the lower portions of the pillars you will have increased hoop stress. If you have too much stress the arch will kick out the sides and collapse. Keep this in mind as you build.

Step 5: Topping Off With a Keystone

Picture of Topping Off With a Keystone

Keep your arch growing until you have a space approximately the shape of a triangle on the top. This wedge piece is call the keystone. This locks in the arch and makes the entire arch lean against itself, thus eliminating the need for your entire support system. This piece needs to fit perfectly. After this piece is placed, it is your last chance to true up the arch. Make any serious adjustments now before the support system is removed.

Step 6: Remove the Supports

Picture of Remove the Supports

Once the arch is completed and you've trued it up and you've filled any cracks with additional snow, it's time to remove your supports. Start at the top, and remove the snow from under the keystone. Then move to either side and take a little more snow out. As you remove snow, see how your arch reacts. Does it sink, settle, and compress more? This might be because you supported it too much. Basically, dismantle your support system very slowly. This is where most arches fail, even stone ones.

Step 7: Enjoy Your Arch

Picture of Enjoy Your Arch

Once you've taken the time to build the arch, make sure you take the time to enjoy it. After all it is snow and won't last forever.

Our arch lasted about an hour before it collapsed. It was way too warm for this one to last, but yours might be able to last for days!

Step 8: What Goes Up, Must Come Down

Picture of What Goes Up, Must Come Down

Watch how the arch changes shape over the one hour of it's life. We noticed where our weak spots were and how a curve that is not perfect is an arch in danger. Check out the final photos and video. The video is the last eight minutes of the arch's life. Each second is about one minute, until the crash. Be sure to watch the slow motion reverse crash. :)

Enjoy your arch making!

Snow Arch from Paul Maiorana on Vimeo.


canida (author)2009-01-11

Cool! Now all I need is snow...

gmjhowe (author)canida2009-01-11

*hands snow*

canida (author)gmjhowe2009-01-11

*makes sad face as it melts immediately* It was 70F here today. Not so good for snow.

jongscx (author)canida2009-01-11

Are you Canidian?

Arbitror (author)jongscx2010-01-24

Heheh, I'm a Canadian, and I also know it snows in the US.

By the way, I don't live in an igloo, there is only snow here for one of the seasons!

andrew_29 (author)Arbitror2010-01-26

  i live in ottawa canada and there is snow just about 6 months a year and i make a half pipe and an iglu every year!

Arbitror (author)andrew_292010-01-26

I love where I live, because the seasons are pretty much balanced. There is basically 3 months of each season.

awesume (author)Arbitror2010-09-11

I live in Texas. And no I don' live in the middle of no where I live in dallas 6th most populated ciy in the US. We get snow about every other winter. in summer this year the highest temperture was 115 degrees F.

firefly68 (author)awesume2011-12-06

awesume, you gave me a good laugh! I lived in Dallas one winter and it snowed all of 1/2". It shut the whole city down! Coming from the northeast, I was in shock at the effect such a teeny little dusting could have on such a huge city. It's understandable, but it was surprising.

awesume (author)Arbitror2010-09-08

Duh! Who is that stupid?

gmjhowe (author)canida2009-01-12

And, may i ask, with all your wondrous items e.g. your laser cutter, why do you not have a snow machine? Laser cutter, but no snow machine... doesn't sound good enough to me!

canida (author)gmjhowe2009-01-18

See comment above; it would melt as fast as we could make it! Unfortunately we have to drive to the Sierras to get cold snowy weather.

Pie Ninja (author)canida2010-01-08

I live in Australia, there are very few places here where it snows. :L

awsome username!

Why thankyou, fellow Hitchhiker's Guide to the Galaxy fan.

join my group!

jcksparr0w (author)2011-09-26

reminds me of the old game arch rival. am definitely going to try this winter!!

ssully1210 (author)2010-01-08

Hey, how about for your next project you make a snow Stonehenge?  build it, let it freeze up and then on next warm day, snow on ground will melt off leaving what would look like stone from a distance.  Don't have big enough yard, or I would try it myself!

tristantech (author)ssully12102011-01-16

Except that it'd be called Snowhenge!

finfan7 (author)2010-08-09

I live in tucson, AZ in the middle of the sonoran desert.. If I didn't I would build lots of these. These are awesome.

crestind (author)2010-02-19

Damn. My triumphal arch does not compare. Definitely could have lasted much longer with better snow.

bassclarinet23 (author)2009-01-16

Great while it lasted? You need wet snow probably.

 i was thinking if it's cold enough you could slowly pour water on it, and hope it'll ice up and stay in place... It's supposed to snow a lot this week where i live, and i'm hoping to make an igloo version of this

andrew_29 (author)2010-01-26

 thats awesome man but in my limited experience with snow you have to let it set over night with the support system and take the structure down in the morning this will let the packing snow freeze so it wont fall over :)  sweet Instructable man

coswine (author)2010-01-25

Great job!  I wonder how much the warmth had to do with it falling.  The left side (in the photo) has a pronounced kink that likely led to the collapse.  I think with the tension equally distributed your arch would have lasted longer...

luvit (author)2010-01-10


ferrari484 (author)2010-01-08

 My brother made a iglo. It was about 1.5m high and 1.5 wide.  Even had a small arch at the front. It stood almost for week. And the remains are still there. And we made it about three weeks ago. But is freezing a lot. So.

CerealKiller (author)2010-01-07

They have something similar here at the St. Louis Science Center but they use foam blocks.

_fatguy (author)2010-01-07

Superb idea, and a really well written and illustrated instructable. Thank you.
How many attempts did your first arch take?

DainiusGB (author)2010-01-07

 nice Idea! but actually brunelleschi's dome structurally was a perfect half circle, not the pointed arch like you have. The pointed dome that you see on the outside was mainly just a kind of skin and structural support (ive been inside it.) 

thing 2 (author)2010-01-01

You should make it so
that one of the blocks has a stick with string around it!

So that when someone walks under it *yank* it all falls on top of them!

volquete (author)2009-01-21

:( no snow in Cali yet........or ever...........

octopuscabbage (author)volquete2009-12-27

pray for global warmin lol

bassclarinet23 (author)2009-11-08

This is awesome....1 more month until winter!!!!

zombiehottie0900 (author)2009-02-18

freaking gorgeous

we built some thing liek this for my aunts community when we visited up north in december and we made an arch/wall thing with the comunnity's logo sighn magig and we and my lil bro just got bored so we did it and the president of the home owner association payed us $50 each for it i wishh i took pictures but my aunt says its still hasnt melted yet so yeah XD

Berkin (author)2009-01-17

Great idea, but you should have used a bit of water in the weak spots and let it freeze into ice. Before it fell, I could already tell which area of the arch was going to fail, because that side was sagging slightly, wasn't built as rigid as the other side. I can also tell that the blocks were more uneven in that area, adding to the potential collapse of the entire structure.

DaPaulness332 (author)2009-01-15

sounds fun, it's supposed to be in the negative 20's where I live tommorow, sounds like a fun snow day project

mtm101097 (author)DaPaulness3322009-01-16

where do u live tommorow?

sounds like a Michigan type area. maybe a surrounding state?

bizydad (author)2009-01-16

Congratulations.....pretty friggin sweet!

samirsky (author)2009-01-15

Cool Arch!

Detail question:
Can you show example syntax to embed a Vimeo video in an instructable?

I found the instructable on embedding video ( which mentions how to for several video sites, but not Vimeo.


hockeyrink (author)2009-01-15

If you're a bit of a woodworker, build this frame to make a long and easy one. Love this project!

=SMART= (author)2009-01-14

wow this is amazing !!, If it was really cold and it lasted for a week or mere that would be so cool !! LOVE the video too :P

dsman195276 (author)2009-01-13

sweet! i might try this since we just got around a foot of snow where i live.

inquisitive (author)2009-01-13

excellent...if you get a good freeze this would be cool with blocks of ice and some led lights.

Plasmana (author)2009-01-12

Wow! That is so cool!

But, for me, it is too warm for snow to form in the UK... :-(

Sunkicked (author)2009-01-12

This is pretty awesome guys. If/when it snows here in Southern Indiana I'm gathering the gang and we are going to be the be the talk of the neighborhood!

moisture (author)2009-01-11

Awesome stuff! And great video. If it were still below freezing when you made it, do you think you could strengthen the arch by carefully pouring water on it and letting the water freeze?

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