How can I freeze a river?

[Huldaerus]

How can I freeze a river other than natural climate? I'm planning a plot around that, and I want to know how that could be done. Spells, monsters, magical items... every idea is welcome.

[Albions_Angel]

By making it very cold...

Joking aside, it depends on the river. No, im serious. If its fast flowing, wide and deep, im sorry but chances are you wont be able to.

Ways to do it would be to tackle the source. Freeze that and the river just dries up. An ice wall that forms a damn would also work.

If you want to actually freeze it, well I would take a look at Frostburn. The book is themed around ice and snow and should have something in it. Other things would be control weather and fimblewinter. Both should, with enough time, put a layer of ice on top of the river, thick enough to walk on.

[Jormengand]

Cha (http://www.d20srd.org/srd/divine/divineAbilitiesFeats.htm#persistentSpell)-ching (http://www.d20srd.org/srd/spells/freezingSphere.htm).

I suggest easy metamagic persist, practical metamagic persist, and arcane thesis freezing sphere to drag it back down to ninth level.

[Albions_Angel]

Cha (http://www.d20srd.org/srd/divine/divineAbilitiesFeats.htm#persistentSpell)-ching (http://www.d20srd.org/srd/spells/freezingSphere.htm).

I suggest easy metamagic persist, practical metamagic persist, and arcane thesis freezing sphere to drag it back down to ninth level.

My worry with something like that is that the flow of the river is far, far more powerful than the strength of the ice, so all you really do is send a bunch of ice chunks cascading down the river... forever.

[Jormengand]

My worry with something like that is that the flow of the river is far, far more powerful than the strength of the ice, so all you really do is send a bunch of ice chunks cascading down the river... forever.

I dunno, 750 cubic feet of ice, weighing over 20 tons, is going to stop most things in their tracks.

[Beheld]

Control Temperature from Frostburn can just set the temperature to -40 Degrees. That usually can manage. For exceptionally large rivers you may need to Wall of Stone it up.

[Albions_Angel]

I dunno, 750 cubic feet of ice, weighing over 20 tons, is going to stop most things in their tracks.

Part 1, this is a river that has literally cut its way through the surface of the planet.

Part 2, saying 750 cubic feet is a little misleading. Sure, the number is correct, but its actually only 6" in depth. You or I would struggle to break that, but when you have a river, flowing at (eg Danube river) 2200 cubic metres per second, when its cross section is probably a semicircle 15m in radius, giving the water a speed of 6 metres a second (thats fast), with each cubic metre of water weighing 1 tonne, even just the top 6 inches + turbulence created underneath the ice, thats a huge amount of pressure. I mean each cubic metre effectively has a momentum of 6000 kg m / s. The ice would break and crack and flow down. The river would not be frozen over permanently, though the production of ice would be permanent.

[Jormengand]

Part 1, this is a river that has literally cut its way through the surface of the planet.

Part 2, saying 750 cubic feet is a little misleading. Sure, the number is correct, but its actually only 6" in depth. You or I would struggle to break that, but when you have a river, flowing at (eg Danube river) 2200 cubic metres per second, when its cross section is probably a semicircle 15m in radius, giving the water a speed of 6 metres a second (thats fast), with each cubic metre of water weighing 1 tonne, even just the top 6 inches + turbulence created underneath the ice, thats a huge amount of pressure. I mean each cubic metre effectively has a momentum of 6000 kg m / s. The ice would break and crack and flow down. The river would not be frozen over permanently, though the production of ice would be permanent.

You can always cast it multiple times.

[Albions_Angel]

I understand you can cast it multiple times, im just skeptical it would do very much with the depth restriction. Either you freeze the whole thing all at once, or you do it "naturally", dropping the temp and having ice slowly build along the edges until it either reaches equilibrium between being broken down and growing, or until it manages to freeze over. Like the Thames.

Like I said before, it depends on the river, its shape, rate of flow, depth, even the geology around it.

[Troacctid]

Research a custom spell.

[Jormengand]

I mean, the other option is to drop a Fimbulwinter on it, but I'm not even sure that will do anything except give you a massive glacier.

[ben-zayb]

Another spell from Frostburn would be Frostfell (Druid 8, Sor/Wiz 9), which does this by instantly adjusting the temperature by 3 bands at a time (to a minimum of unearthly cold) on an Area: 20ft cube/level

[GnomishPride]

Duh, cast Nailed to the Sky on that pesky river. Rivers in space tend to freeze. YRMV

[danddbard]

wish spell. gotta warp reality for this one

[Jormengand]

Duh, cast Nailed to the Sky on that pesky river. Rivers in space tend to freeze. YRMV

I imagine the river weighs more than 1000 lb, which is of course the principal reason why this wouldn't work.

[Extra Anchovies]

I imagine the river weighs more than 1000 lb, which is of course the principal reason why this wouldn't work.

No, see, the water in the river weighs a lot, but the river itself doesn't weigh anything - it's the space through which the water is flowing. So it works just fine!

[Jormengand]

No, see, the water in the river weighs a lot, but the river itself doesn't weigh anything - it's the space through which the water is flowing. So it works just fine!

Space isn't an object. :smalltongue:

[GnomishPride]

I imagine the river weighs more than 1000 lb, which is of course the principal reason why this wouldn't work.

But if the river is in space, it has no weight.

[Jormengand]

But if the river is in space, it has no weight.

Yeah, but when you target it with the spell, it's not in space.

[TheBrassDuke]

A simple Orb of Ice/Cold should do the trick.

[GnomishPride]

Yeah, but when you target it with the spell, it's not in space.

Little details. :smalltongue:

[KingSmitty]

im sure a red wizard using circle magic to get a CL of up to 40 can cast one wall of ice spell and would be pretty well off.

[Jack_Simth]

Flash Freeze, Druid-2, from Frostburn. Earth, Mud, and Stone affected become Everfrost, which apparently never melts. It doesn't care about the climate, and it's an Instant effect. Also freezes water to a depth of 1 foot. Combine with Fimbulwinter every now and again to keep the water frozen (Frostburn page 93, Druid-8, Cleric-9, Sor/Wiz 8), and you're there.

[Shalist]

There's always the classics (http://dragonlancenexus.com/lexicon/index.php?title=Lauralanthalasa_Kanan#War_of_the_L ance), if you happen to have scaly friends in high places:


...This Dragonarmy force greatly outnumbered her army, but Laurana devised a plan that succeeded in destroying the vast enemy army by first having her silver dragons create an ice dam in the Vingaard River, and then having her gold dragons melt the dam when the Dragonarmy forces attacked across the now dry riverbed, unleashing a tidal wave that utterly destroyed the Dragonarmy ground force while Laurana led the good dragons to defeat the enemy dragons in the largest aerial battle of the war...

[Ruethgar]

Hmmm, Create Water that is frozen(ice is still water), get access to the spell as an SLA through one of various means with Ocular, Ray Extension, Persist Extend, Split, Chain, Twin, Repeat, War on it for a 25ft cube of ice per concentration, of which you can get 4 per round. A 25ft by 50ft by 50ft wall of ice isn't that much, but could appear to freeze a significant portion of a river.

That's 62,500 cubic feet of ice which is a tad more significant than the aforementioned 750 cubic feet.

[Spore]

Don't overcomplicate things. Summon in Ice Elementals or use a permanent Gate to the coldest place in existance.

[Bronk]

How can I freeze a river other than natural climate? I'm planning a plot around that, and I want to know how that could be done. Spells, monsters, magical items... every idea is welcome.

For magic items, there would be the 'Major Iceheart'. It freezes the area around it, and casts the 'fimbulwinter' spell once per day, by itself, whether you want it to or not! You could have one or more of these around, and every day when the spell is cast, it would get colder and colder for miles around.

[tropical_punch]

Duh, cast Nailed to the Sky on that pesky river. Rivers in space tend to freeze. YRMV

I wouldn't want to be that guy, but if you dump a liquid in space it's going to boil immediately. Primarily because of the lack of pressure, but even if it weren't for that, things in space actually heat up because they can only lose heat through thermal radiation, and take in heat from all that same radiation in space (from stars and so forth). And that tends to be quite a bit without an atmosphere to protect you.

[Albions_Angel]

I wouldn't want to be that guy, but if you dump a liquid in space it's going to boil immediately. Primarily because of the lack of pressure, but even if it weren't for that, things in space actually heat up because they can only lose heat through thermal radiation, and take in heat from all that same radiation in space (from stars and so forth). And that tends to be quite a bit without an atmosphere to protect you.

While you are right on the boiling thing, if you are gunna be that guy, you should be honest about the temp. Things in the suns light can get VERY hot. But in the shadow of the earth or other body, they do get VERY cold. Earth sits in the habitable zone, but only just. If we didnt have an atmosphere, we would be snowball. Most water in our vicinity is frozen. And further out than us, almost all of it is either vapor or ice, with the dominance in the solar system being hugely ice outside of planetary atmospheres. Comets, for example, are frozen.

The radiation from other stars in negligible. Radiation falls off with radius squared. A cube of water in space (ok, a sphere) will radiate way more heat than it gets so long as its not in direct sunlight.

You may be confusing the "temperature" of the upper atmosphere. The air up there is so thin that you dont measure temperature normally. Instead, you have to calculate the thermodynamic temp. Usually, the thermodynamic temp and the regular temp (what you feel) are the same thing. But up there, the thermodynamic temp, the kinetic energy of the particles, is very high, but those particles are so far apart, there is more space between them than there are particles usually. (In more precise terms, above the exobase, the mean free path of a particle is greater than the scale height of the atmosphere, roughly 10km for earth) What does that mean? While each particle carries tremendous energy, and thus has a high thermodynamic temperature (many thousands of degrees), collisions with objects are so rare, that objects feel very cold, radiating heat much faster than the surrounding particles can transfer it to them.

Sure, water boils in space because of the low pressure, but dont kid yourself that a large body wouldnt freeze before it all boils away. Just look at mars, or europa, or any comet.

Source: 4th year Astrophysics Masters student.

[tropical_punch]

Good point. It would be very cold if you were behind a body in space. I didn't even consider that, although I believe nailed to the sky makes the target orbit the planet, so sometimes it would be exposed, other times it would be shaded. But it still wouldn't lose heat very quickly when shaded by the planet, since the heat can only radiate away (i.e. it would be slower than when the river cools down when on the planet).

[Aletheides]

Depends on the scope of what you're trying:

Are you wanting to freeze the ENTIRE river, from source to mouth? Wish or Miracle...maybe. Lots of unforeseen consequences with this, rivers usually support a lot of life and territory, whose denizens/protectors you'll be annoying slightly. :smallamused:

Are you wanting to freeze, or dam up, a large segment of the river to stop the water for a certain period of time? Lots of options for flash-freezing an area of water. Freezing Sphere, Cone of Cold (widened?), and others can get things rolling, but to shore it up against the water pressure and limit overflow, you'd want to lay down other barriers before the ice gives way. Time Stop might be helpful.

Once the flow is slowed enough, throw in more mass-freezing magic; one trick an evoker of mine used to freeze large areas of water was a Wall of Fire, shifted to cold damage--the wall itself, plus the radiant energy from the wall, is a little slower, but can freeze huge areas as long as the caster keeps it up.

If you're the DM looking for a handwave, making it a custom researched spell or ritual isn't too unbelievable. Look at the Cursed Earth spell...A spell that could curse a river into freezing doesn't seem too different, power-wise.

Good luck!