Wow, there is a lot in the WSG about wind.
Table 5: Wind Velocity Effects
eg Wind velocity 21-30 Missile combat will be at -1 point blank, -2 short range, -3 medium range and impossible long range; -1 melee combat, move into the wind 3/4 normal.
Wind velocity is in miles per hour.
I am yet to find a table that randomly assigns wind velocity - found it in the weather appendix page 109. Stay with me until W - that's the big one for the WSG.
But if one wanted to have a wind increasing through the stages, during combat for example, this could be interesting worsening effects until 80+ miles per hour.
Then we have passed from gales into worse.
A gale is winds 46-79 miles per hour. The DM may require, in severe gales, to make a Str check every round / turn (depending on severity) to see if the character is knocked off their feet and suffers 1d3 damage.
Cyclones and Hurricanes
Instructions are given for how a character can hollow out a hole in the ground and lie face down in it. A Str check as above may be required if no protection from the wind is possible. Standing up requires strength checks every round at +2 penalty.
Table 6 gives rules for Structural damage of the winds intensity, as given by a rating of light, normal, heavy against wood, earth, sort stone and hard rock. 50% chance every 3 turns structure takes that damage. This is linked to page 110 DMG where many constructions are listed with their Defensive Point Value. I like this, using and building on, what is already there in the core AD&D knowledge base.
A cyclone or hurricane usually starts as light and moves over many hours into normal and then some will even move onto heavy (200 miles per hour). So that Str check every turn would soon kill most normal men and characters, if they are foolish enough to be out in the storm.
Tornados, as my relatives in Texas this week can attest, are forces of nature best avoided. The WSG suggests that a tornado, owing to their small area of effect, are usually quite easy for a group of players to avoid.
If they do not - 4d20 damage by debris battering damage, lifted 1d6 x 10 feet off the ground and carried along for 1d6 x 100 yards and then dropped... remembering the Falling Post yesterday, where anything over 51 feet fall is 20d6 and even 41-50 feet is 15d6!
Despite tornadoes being easy to avoid, they surprise on a 1 on a d6, 1-2 at night.
Tornados have their own seperate table for damage to buildings. DM discretion if tornado hits building.
Roll 1d6, refer to building type
Either '-' = no damage
'D' = Damaged, lose half defensive point value, and occupants take 3d6 damage.
'X' = Destroyed, 3d10 damage to each occupant, 1in10 chance that single character determined randomly, swept up with tornado with damage as above.
All interesting little facts, to make wind, a monster and chief protagonist in an encounter.