Re: Why is wind a problem
NASA has done extensive research into this. For the shuttle for instance it was:
"Wind: Tanking will not begin if the wind is observed or forecast to exceed 42 knots for the next three hour period.
For launch the wind constraints at the launch pad will vary slightly for each mission. The peak wind speed allowable is 30 knots. However, when the wind direction is between 100 degrees and 260 degrees, the peak speed varies for each mission and may be as low as 24 knots."
If you want to read a full study on wind effects (this one is from 1966, 435 pages) go here: http://ntrs.nasa.gov/search.jsp?R=19660022936
"Ground wind load effects on launch vehicles and circular cylinders - conference "
You will see that there are a couple of issues with wind, including nearby objects, vibration, trajectory of parts falling back to earth, etc. It also has a nice pic of one of their test models being blown over from its platform in a storm.