Step 1: Find a good spot
A field where the snow is hard, normally where the snow has melted and refrozen is good. It needs to be hard enough to make solid snow blocks. Even if the top layer of snow is soft, normally you can find harder snow underneath. Use something like a sticks to make a circle to mark the footprint of the Igloo. The snow should be at least 3 feet or 1m thick where the igloo is placed. Normally Igloos should be built to sleep 2-3 people.
Step 2: Preparing the snow blocks
Snow blocks are easiest to prepare with a saw(a hand wood saw works great) but use what you have. they should be strong enough to carry and not have them break under their own wait. Use larger blocks at the base of the Igloo with them getting smaller as you ascend, 8 to 12 inches or 15-30cm is good thickness. Leaving the blocks out in the wind will make them extra hard.
Step 3: Start building the Igloo
Smooth and angle the edges of the blocks to make the joints as tight as possible. Some gaps and cracks are normal, those will be fixed later. Its crucial to start the bottom blocks at a slant, otherwise your structure won’t be a dome.Build a full circle of blocks, one person should be working from inside the Igloo ( if built correctly, they should have to cut them selves out to bring in the top piece to the dome). To make construction easier, try to build it in an ascending spiral. At this stage it might look small, but you will dig more snow out later. By now the dome should star to form, removing excess snow as you go can be easier than waiting to the end. If done correctly, the dome will be strong because each block you place is supported by the block you placed before. If you need you can use something to support the the upper dome as you build it, and remove it when you’re done. The last few pieces will be fed through the door that you need to cut into the base. The hall way that leads to the door is made of two blocks of ice leaning together like an upside down “V”.
Step 4: Finishing the Igloo
Ok so it’s closed in and looks kinda like the pictures ( well close). Now its time to fill in the big cracks with pieces of snow cut for them, and loose snow for the small ones. Make sure to smooth the inside of the dome so that there is no dripping of water when it gets warm inside. After its smooth, its time to clear out the rest of the snow and finish the entrance like i talked about in the paragraph above. If you want an entrance that won’t let in any wind or snow, you dig an “L” shaped trench and cover it with blocks.A cold sink is crucial! weather you dig the entrance nice and deep and use that or you dig an actual cold sink inside the igloo is up to you. use something to insulate your self from the floor, like a foam mattress or whatever you have. Also make sure to have some ventilation holes to allow fresh air in, especially if you are going to be cooking inside or using a candle or lamp.