How to Keep Your Yurt from Blowing Away, Part 2

The information in this post comes from Peter Andrews' book Nomadic Tents of the Middle East. See previous post for a review of that book.
The nature of tents is that they are sufficiently light so they can be transported by whatever means are available.  That used to be pack animals, but now among the remaining nomads it could be a truck as well. But the light weight of a tent makes it vulnerable to wind.  If the tent is not sufficiently staked down, it may well be blown away.  In the case of my twelve foot yurt, I put stakes into the ground around the perimeter of the yurt and tied lines to them that ran up to the edge of the roof.
In the case of the Iranian nomads in Andrews' book they drive a stake into the ground in the center of their tent and run lines from the perimeter of the crown down to the stake.  While this arrangement helps to keep the tent anchored in a storm, it also has structural functions.

Perspective drawing of Iranian yurt. The stake to which the crown is anchored is visible just above the center of the door. 

Unlike the more familiar Mongolian yurts with their trellis walls and conical roofs, the frame of this yurt is made up of arched poles whose upper ends are set into mortises in the crown giving this tent a dome shape.  Bands wrapped around the arched poles keep their spacing consistent.  Once the frame is erected, lines are run around the crown and are then pulled down and anchored to the stake in the center of the tent.  The tension of the anchor rope flattens the roof and puts the frame under compression, making it stiffer and making the upper ends of the poles come into the crown from the side in the horizontal plane.  The stake is probably used primarily to force the tent into its proper shape.  Nevertheless, the anchor rope must also help to keep the tent in place in a storm.

Photo of the anchor rope running from the crown down to the center stake. The stake is driven into the ground to a depth of about 3 feet.

Details of stake, mallet and alternative method of anchoring the crown.

In places where the ground is too hard to drive a stake into, the anchor rope is run around a pile of rocks that act as the anchor.
This scheme of anchoring a yurt would probably not work as well for a yurt with trellis walls because the trellis sits on the ground and unlike the poles of this Iranian tent are not pushed into the ground which is what keeps them from shifting sideways.  In any case, the central anchor is probably something to consider for the would-be yurt builder.
By the way, these illustrations show the degree of detail Andrews' book contains.  For this particular tent, Andrews has several more pages of detail on everything from crown construction, to cover tailoring to tools used in the construction of the frame.