Here's a kind of.. experimental world/embark.
I was playing around with temperature extremes to find out the limits of colddamage and melting, to see what would be the actual ranges in worldgen with poles and world sizes.
Inadvertently, I found an embark where the water on the surface turns to steam, while the river is running. Specifically, the outside surface temp transitions to higher than 10180'U, within an embark with a river on it.
Then my goal was to find an embark with a tolerable temperature range
combined with a boiling river.
Thus I give you:
Ecruletters, the steam river embark!worldgenCreated in DF v0.40.12.
[WORLD_GEN]
[TITLE:ECRULETTERS]
[SEED:w4IGWUOqSCCMI2UsCaeQ]
[HISTORY_SEED:WgGsOOYSCMckeQGgUiiK]
[NAME_SEED:Eec80kEgImQWM2smccSy]
[CREATURE_SEED:AuwoK4EUC42aSKauqgy0]
[DIM:33:33]
[EMBARK_POINTS:5000]
[END_YEAR:100]
[BEAST_END_YEAR:100:-1]
[REVEAL_ALL_HISTORY:1]
[CULL_HISTORICAL_FIGURES:0]
[ELEVATION:1:400:0:0]
[RAINFALL:100:100:0:0]
[TEMPERATURE:0:300:3200:3200]
[DRAINAGE:49:50:3200:3200]
[VOLCANISM:0:0:0:0]
[SAVAGERY:0:0:0:0]
[ELEVATION_FREQUENCY:1:1:1:1:1:1]
[RAIN_FREQUENCY:1:1:1:1:1:1]
[DRAINAGE_FREQUENCY:1:1:1:1:1:1]
[TEMPERATURE_FREQUENCY:1:1:1:1:1:1]
[SAVAGERY_FREQUENCY:1:1:1:1:1:1]
[VOLCANISM_FREQUENCY:1:1:1:1:1:1]
[POLE:NORTH]
[MINERAL_SCARCITY:1000]
[MEGABEAST_CAP:0]
[SEMIMEGABEAST_CAP:0]
[TITAN_NUMBER:0]
[TITAN_ATTACK_TRIGGER:40:0:0]
[DEMON_NUMBER:2]
[NIGHT_TROLL_NUMBER:0]
[BOGEYMAN_NUMBER:0]
[VAMPIRE_NUMBER:0]
[WEREBEAST_NUMBER:0]
[SECRET_NUMBER:0]
[REGIONAL_INTERACTION_NUMBER:0]
[DISTURBANCE_INTERACTION_NUMBER:0]
[EVIL_CLOUD_NUMBER:0]
[EVIL_RAIN_NUMBER:0]
[GENERATE_DIVINE_MATERIALS:0]
[GOOD_SQ_COUNTS:0:0:0]
[EVIL_SQ_COUNTS:0:0:0]
[PEAK_NUMBER_MIN:0]
[PARTIAL_OCEAN_EDGE_MIN:0]
[COMPLETE_OCEAN_EDGE_MIN:0]
[VOLCANO_MIN:0]
[REGION_COUNTS:SWAMP:0:0:0]
[REGION_COUNTS:DESERT:0:0:0]
[REGION_COUNTS:FOREST:0:0:0]
[REGION_COUNTS:MOUNTAINS:0:0:0]
[REGION_COUNTS:OCEAN:0:0:0]
[REGION_COUNTS:GLACIER:0:0:0]
[REGION_COUNTS:TUNDRA:0:0:0]
[REGION_COUNTS:GRASSLAND:0:0:0]
[REGION_COUNTS:HILLS:0:0:0]
[EROSION_CYCLE_COUNT:999]
[RIVER_MINS:0:0]
[PERIODICALLY_ERODE_EXTREMES:0]
[OROGRAPHIC_PRECIPITATION:0]
[SUBREGION_MAX:2700]
[CAVERN_LAYER_COUNT:1]
[CAVERN_LAYER_OPENNESS_MIN:0]
[CAVERN_LAYER_OPENNESS_MAX:0]
[CAVERN_LAYER_PASSAGE_DENSITY_MIN:0]
[CAVERN_LAYER_PASSAGE_DENSITY_MAX:0]
[CAVERN_LAYER_WATER_MIN:51]
[CAVERN_LAYER_WATER_MAX:60]
[HAVE_BOTTOM_LAYER_1:1]
[HAVE_BOTTOM_LAYER_2:1]
[LEVELS_ABOVE_GROUND:10]
[LEVELS_ABOVE_LAYER_1:8]
[LEVELS_ABOVE_LAYER_2:20]
[LEVELS_ABOVE_LAYER_3:2]
[LEVELS_ABOVE_LAYER_4:2]
[LEVELS_ABOVE_LAYER_5:3]
[LEVELS_AT_BOTTOM:2]
[CAVE_MIN_SIZE:1]
[CAVE_MAX_SIZE:1]
[MOUNTAIN_CAVE_MIN:0]
[NON_MOUNTAIN_CAVE_MIN:0]
[ALL_CAVES_VISIBLE:1]
[SHOW_EMBARK_TUNNEL:2]
[TOTAL_CIV_NUMBER:3]
[TOTAL_CIV_POPULATION:2]
[SITE_CAP:20]
[PLAYABLE_CIVILIZATION_REQUIRED:1]
[ELEVATION_RANGES:0:0:0]
[RAIN_RANGES:0:0:0]
[DRAINAGE_RANGES:0:0:0]
[SAVAGERY_RANGES:0:0:0]
[VOLCANISM_RANGES:0:0:0]
[PS_EL:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400]
[PS_EL:400:400:400:400:400:400:400:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:400:400:400:400:400:400:400]
[PS_EL:400:400:400:400:400:400:400:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:400:400:400:400:400:400:400]
[PS_EL:400:200:100:148:146:144:142:140:138:136:134:132:130:128:126:124:122:120:118:116:114:112:110:108:106:104:102:100:100:100:400:400:400]
[PS_EL:400:400:400:400:400:400:400:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:400:400:400:100:400:400:400]
[PS_EL:400:400:400:400:400:400:400:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:400:400:299:100:299:400:400]
[PS_EL:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:100:400:400:400]
[PS_EL:400:400:400:400:400:400:400:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:400:400:299:100:299:400:400]
[PS_EL:400:400:400:400:400:400:400:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:400:400:400:100:400:400:400]
[PS_EL:400:400:400:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:400:400:400]
[PS_EL:400:400:400:100:400:400:400:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:400:400:400:400:400:400:400]
[PS_EL:400:400:299:100:299:400:400:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:400:400:400:400:400:400:400]
[PS_EL:400:400:400:100:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400]
[PS_EL:400:400:299:100:299:400:400:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:400:400:400:400:400:400:400]
[PS_EL:400:400:400:100:400:400:400:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:400:400:400:400:400:400:400]
[PS_EL:400:400:400:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:400:400:400]
[PS_EL:400:400:400:400:400:400:400:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:400:400:400:100:400:400:400]
[PS_EL:400:400:400:400:400:400:400:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:400:400:299:100:299:400:400]
[PS_EL:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:100:400:400:400]
[PS_EL:400:400:400:400:400:400:400:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:400:400:299:100:299:400:400]
[PS_EL:400:400:400:400:400:400:400:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:400:400:400:100:400:400:400]
[PS_EL:400:400:400:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:400:400:400]
[PS_EL:400:400:400:100:400:400:400:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:400:400:400:400:400:400:400]
[PS_EL:400:400:299:100:299:400:400:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:400:400:400:400:400:400:400]
[PS_EL:400:400:400:100:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400]
[PS_EL:400:400:299:100:299:400:400:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:400:400:400:400:400:400:400]
[PS_EL:400:400:400:100:400:400:400:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:400:400:400:400:400:400:400]
[PS_EL:400:400:400:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:400:400:400]
[PS_EL:400:400:400:400:400:400:400:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:400:400:400:100:400:400:400]
[PS_EL:400:400:400:400:400:400:400:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:200:400:400:299:100:299:400:400]
[PS_EL:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:100:400:400:400]
[PS_EL:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:299:100:299:400:400]
[PS_EL:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:400:100:400:400:400]
embark location The important part is to embark on the second biome, that is, to have the F2 biome (the warm tropical moist forest) highlighted when you embark, so all the dwarves and animals don't instantly melt and die when you start/unpause.
Otherwise, it's pretty neat to see. I have no idea if dwarves like steam, or if the steam could be weaponized in some way, but it's a hella neat effect when it starts raining in the boiled-dry riverbed, let me tell you. Also, the second river that runs north is also boiling dry in it's path, and is nearby in the embark.
To be clear: The only safe surface portion of this embark is the SouthEast corner. Everywhere else, everything melts/boils to death.
And yes, this could be done without the world painter, I was hoping for a steam waterfall, but couldn't find one quickly/easily.