All commanders wish that any engagement they fight would occur under ideal weather and terrain conditions; neither too hot nor too cold, with clear skies and dry, solid ground underfoot. Unfortunately, most battles are fought in less than favorable conditions. Often, summer's heat adds to the strain already placed on overworked heat sinks, or winter's cold thickens lubricants and freezes joints. Rain, fog, and blowing snow or dust obscure vision, making it difficult to establish hard targeting locks on the enemy. Heavy precipi- tation turns battlefields into 'mech-trapping quagmires. Aircraft are even more prone to the ill effects of bad weather than are ground units. Reduced visibility impairs the pilot's ability to maneuver his craft, often with fatal results. Some small, light aircraft, such as the Ferret light scout VTOL, are unable to fly at all in bad weather, particularly if strong winds are involved. Infantry and tracked or wheeled vehicles (BUT NOT MECHS) can easily bog down in muddy fields, drifted snow, or sand dunes. Only hovertanks are able to cross most kinds of terrain with impunity. However, even they are susceptible to being grounded if high winds disturb their rather delicate air-cushion. Following is a set of rule variants/additions for the Battletech combat simulator system. These changes will allow combat instructors and civilian game referees to provide for the adverse effects of bad weather on the movement, combat, and maintenance of Battlemechs and other modifications to combat systems. (see also Hostile Environments, P 57 in The BattleTech Compendium, published by the FASA Corporation.) TERRAIN MODIFIERS TO MOVEMENT AND SKILL ROLLS WeatherlTerrain Type Cost Per Hex Ground AirlAerospace Mud +1 mp* N/A Ice **see compendium N/A Fog / Rainfall/Snowfall +1 mp/hex*** +1 mp/hex Deep Snow**** +1 mp* N/A * increase movement cost to enter hex by 1 Thus a muddy clear hex costs 2 M P to enter, a deep snow light woods hex costs 3 M P to enter) **Even while walking, apply skidding rules, BattleTech Compendium *** Infantry only. 'Mechs, because of visibility problems, while running, make piloting skill roll at -2 to avoid failing. **** 1 level deep (5m) Other Effects are: treat as partial cover: +3 to hit, but all hits on the Punch Location Table Air/Aerospace Skilll Roll Modifiers Condition : Piloting Skill Modifications Rain +1 Heavy Rainfall/Snowfall +2 Fog +3 Rotor Hit (VTOL) +1 Control Surface Damaged +3 High Wind : +1 plus weight modifier Weight Modifier of: Jump Infantry (to take off) +2 up to 25 tons +3 25 to 55 tons +2 55 to 75 tons +1 75 to 100 + tons 0 MOVEMENT Bad terrain and inclement weather make movement difficult and dangerous for any unit exposed to such conditions. Apply the tables given here for movement costs and piloting skill roll modifiers when any units encounter the listed conditions. Note that there is a special Optional Infantry Target Roll TO-HIT MODIFIER Condition : Modifier Fog/Blowing Sand or Dust/Smoke * +2 Heavy Rainfall / Snowfall +1 general targeting Windy Conditions" as below No/Light Winds 0 Moderate Winds -2 Missile Hit Table; + 2 to-hit w Streak SRM High Winds : +1 to-hit Long Range fire; -4 Missile Hit Table; +4 to-hit w Streak SRM High Winds/Sandstorm : -4 Missile Hit Table; +4 to-hit w Streak SRM; +2 to-hit Long Range Fire; +1 to- hit Medium Range Fire Cyclone : No Missile Fire Allowed; +2 to-hit Long Range; +1 to-hit Medium Range; +1 to-hit Short Range *as Compendium Smoke Rules: Beam Weapons Only **applies to Autocannon, MG, and Missiles only If another unit intends to tow the bogged vehicle out, it must enter the hex directly in front of or directly behind the bogged unit, and spend one full turn in that hex while tow cables are attached, etc. If the towing vehicle enters a hex susceptible to bog-down, it too must make a piloting skill roll to avoid getting stuck while helping the other Imit. It is possible for a bogged vehicle to be freed while the towing unit becomes entrapped. When a vehicle is freed from a bog-down, it must roll 2d6. On any roll of 10-12, it has suffered damages to, its tracks/suspension, which is rolled randomly in the usual manner. Optional Infantry Movement Target Roll Base Number: Green 5 Regular 4 Veteran 3 Elite 2 Bogdown Modification: Jump -1 Mechanized +1 See also air / aerospace rules BOG DOWNS When any Non-'Mech ground unit enters a mud, deep snow, or soft sand hex, that unit must make a piloting or driving skill roll to avoid becoming bogged down. Bogged infantry and vehicles are considered to be trapped or immobilized in the first hex of bad terrain they entered on that turn. The 'Mech or vehicle retains the orientation it had when it entered the bog hex, but it may pivot on its torso, or rotate its turret (if any) in accordance with the rules governing such changes. Freeing a bogged unit is often quite difficult, and sometimes attempts only make matters worse - the bogged vehicle digs itself in deeper, or a towing vehicle gets itself stuck. Frequently, one or both units are damaged in the attempt. Trying to free a bogged-down vehicle necessitates a piloting skill roll. Success indicates that the bogged unit may leave the bog hex. If the next hex contains terrain favorable to bogging down, another piloting roll must be made to avoid getting stuck again. (This may seem excessive, but anyone who has attempted to drive a ground car through mud or deep snow will appreciate the difficulty of such an undertaking.) Piloting Skill/Bog Down Roll Modifiers-Table for Non- 'Mech Vehicles and Infantry units Condition : Modifier Ground Vehicle/ Unit by Weight: Infantry -2 up to 40 tons 0 45 to 60 tons +2 65 to 80 tons +3 over 80 tons +4 Heavy Rainfall/Snowfall* -1 Deep Snow/Soft Sand* +1 Mud +2 Fog +1 High Winds +1 (+3 if jumping) Per wheel/track Hit +1 Per Turn Spent in Bog +1 Bogged Vehicle Using Jumpjets -2** Towing Vehicle Weighs More Than Bogged Vehicle -2 Hovercraft -3 In Heavy Conditions, Affected unit sinks to solid ground & has traction; in deep/soft conditions, Afftected unit tries for traction on intervening substance. ** See Roo Scout, p 45 for amplification HEAT The dissipation of waste heat is also affected by the weather. Rain or snow increases the efficiency of heat sinks, while hot, dry conditions impair their function. Use this table in to modify the heat scale as affected by the weather. HEAT SCALE MODIFIERS Condition Modifier Heavy Rainfall/Snowfall 1/turn Deep Snow* 2/turn Below -300 C** -1 per 100 or fraction below Only if 'Mech in the snow bank, per heat sink in leg only, add to weather mods as per water rules. **Prohibited to Unarmored Infantry NOTE: Rain, snow, and fog make it more difficult to start fires. Add +2 penalty to all fire-starting rolls under wet conditions. COMBAT Poor weather conditions can have a severe effect on combat as well as on movement. Fog, rain, snow, and blowing dust make targeting the enemy difficult. High Winds will interfere with the trajectory of ballistic weapons such as autocannon shells or missiles. To simulate these effects, apply the Combat "to hit" modifiers as appropriate. Weather Table Reprinted with permission from Battle For Twycross, Published by the FASA Corporation See Also Valley of the Four Winds, BattleTechnology # 12 for specialized wind conditions. Die Roll : Result 2 : Cyclone 3 : High Winds/Sandstorm 4 : High Winds 5 : Moderate Winds 6 : Moderate Winds 7 : Light Winds / Clear 8 : Moderate Winds 9 : Moderate Winds 10 : High Winds 11 : High Winds/ Sandstorm 12 : Cyclone Back to BattleTechnology 14 Table of Contents Back to BattleTechnology List of Issues Back to MagWeb Magazine List © Copyright 1990 by Pacific Rim Publishing. This article appears in MagWeb.com (Magazine Web) on the Internet World Wide Web. Other military history articles and gaming articles are available at http://www.magweb.com