_jamChance = _jamChance * ([[0.5, 1, 2, 8, 20, 150], 5 * _scaledTemperature] call EFUNC(common,interpolateFromArray));

// increase jam chance on dusty grounds if prone (and at ground level)
if ((stance _unit == "PRONE") && {((getPosATL _unit) select 2) < 1}) then {
    private _surface = configFile >> "CfgSurfaces" >> ((surfaceType getPosASL _unit) select [1]);
    if (isClass _surface) then {
        TRACE_1("dust",getNumber (_surface >> "dust"));
        _jamChance = _jamChance + (getNumber (_surface >> "dust")) * _jamChance;
    };
};

TRACE_3("check for random jam",_unit,_weapon,_jamChance);
if ((random 1) < _jamChance) then {
    [_unit, _weapon] call FUNC(jamWeapon);
};