Snorunt is only obtainable in Platinum before the postgame. It can be found on routes 216 and 217 as well as Lake Acuity and its lakefront at night. It is a rare encounter on route 126, but a relatively common one in all other locations. Dawn stones can be obtained on route 212 and within Mt. Coronet. Additional dawn stones can be obtained through Pickup.
While male Snorunt are doomed to mediocrity with the no stat higher than 80 Glalie as their only evolution option, the females of the line were granted a split evolution, similar in style to Gallade. Froslass is, despite the torture Candice's one can be to deal with, a difficult Pokémon to use. While it is fast, with an impressive base 110 speed, that is the only stat it has above 100, with its defenses worse than Glalie's. Ice/Ghost is also a dreadful defensive typing, with several key weaknesses. However, while said type is mostly garbage in terms of defense, outside of the handy immunity to Normal and Fighting-type moves, it is incredible on the offensive. Access to STAB Ice Beam and Shadow Ball off the bat is an incredible feat for an attacker, throw in Psychic and Thunderbolt, among other options, and you have a competent sweeper, even if it does need support in order to get things moving.
Gym #7 - Candice (Snowpoint City, Ice-type): Sneasel is risky due to Faint Attack. This is a certain 2HKO on your Pokémon, while Thunderbolt can only 3HKO in response. Piloswine is also a threat as a result of Stone Edge, with Water Pulse/Shadow Ball once more a 3HKO in response to a 2HKO. This once more the case with Abomasnow, with Wood Hammer overpowering Ice Beam, although you can abuse its Snow Warning ability to try and abuse evasion boosts through Snow Cloak. Meanwhile the ditto with her Froslass is a mess, both Pokémon 2HKO each other with Shadow Ball and Snow Cloak turns it into a RNG driven disaster.
Cyrus (Galactic HQ): His Sneasel lacks a Dark-type move, so its manageable through Thunderbolt. Crobat may have Bite, but the lack of STAB and its low power means it is only a 3HKO in contrast to Ice Beam's 2HKO. Honchkrow hits hard with Faint Attack, and a critical hit will kill, but Ice Beam has a chance to OHKO and despite its sitrus berry, Froslass is fast enough to pick it off if the first shot is not enough.
Saturn (Galactic HQ): His Golbat is significantly less of a threat than his master's Crobat was, Ice Beam should deal with it quickly. Bronzor is neutral at best to Froslass' options and its low speed means Gyro Ball hits extremely hard. One Psychic should be enough to deal with Toxicroak.
Mars and Jupiter (Spear Pillar, tag battle with rival): They both lead with Bronzor and atop the misery of Gyro Ball, one has Rock Slide and they have dual screens between them. Certainly not a good start, particularly when the rival's Munchlax is dead weight. While the two Golbat are likely doable with care, both of their aces have multiple ways to kill or cripple Froslass. This fight is a rough one, and you need to remove Munchlax in order to have a competent ally on your side, something Froslass is not achieving before it falls.
Cyrus (Distortion World): Houndoom crushes Froslass with both of its STAB options, don't even bother with Water Pulse, it is not even worth trying. Honchkrow shares a 2HKO between Ice Beam and Night Slash. However its high critical rate makes this a risky endeavor even if Froslass is faster. Crobat is a certain 2HKO with Ice Beam while Air Slash can only 4HKO your Pokémon at best. Ice Shard is noticeable here for being able to pick it off before it gets a second hit due to Crobat's high speed. Weavile actually has a Dark STAB this time around, making this a suicidal fight but Gyarados is a 2HKO with Thunderbolt, while it only has a chance to do the same with Waterfall, just be careful of the quick claw and critical hits.
Giratina (Distortion World): Ice Beam is at best a 2HKO, while Shadow Force obliterates Froslass for daring to even attempt to take on the banished titan. However with the help of a Kasib Berry, suddenly this instant death turns into a 2HKO allowing the faster Froslass to take it out. There are a number of problems here though. If it crits, you still die and if it chooses to use Ancientpower or Ominous Wind instead and gets a stat boost from either of those, bad times are ahead without deploying a Pokédoll or the master ball.
Gym #8 - Volkner (Sunyshore City, Electric-type): Jolteon is 3HKO'd by Ice Beam from Froslass at level 50. This seems decent with Charge Beam being a 4HKO, however Iron Tail has a chance to 2HKO and Thunder Wave serves to complicate matters more. It's certainly a task that Froslass can do, given Iron Tail's shaky accuracy but care is needed. Raichu has a surprisingly good coverage movepool between Signal Beam and Focus Blast, not that it matters to a Ghost-type. Charge Beam is a 5HKO while Ice Beam is the same as it was against Jolteon, but with a high chance of being a 2HKO. Just be wary of boosts given to his Pokémon through their STAB option. While Rivalry does soften the blows delivered by his Luxray, Crunch still has a chance to 2HKO while Ice Beam only manages a 3HKO in response, and a defense drop will force Froslass out. Electivire just kills you with Fire Punch faster than Froslass can to in exchange. Avoid this one.
Rival (Pokémon League): Staraptor is an easy OHKO with Ice Beam. Now on to those who might actually put up a fight (besides Torterra, rip in 4x weakness to Ice). At level 53, you need a critical or a boosting nature in order to OHKO his Roserade, which happily slashes between 52 and 62% of your Pokémon's hp in response, also scoring an OHKO if Shadow Ball crits. Floatzel is a in a similar boat, while Thunderbolt is a certain 2HKO in comparison to the chance that Crunch does, Aqua Jet can be nightmarish if Froslass withstands a critical hit, watch your health or send in something stronger. Snorlax could not care about what Froslass has to hit it with, Ice Beam struggling to 4HKO while its Crunch is a certain 2HKO. Rapidash 2HKOs with Fire Blast, just no. Heracross is going to 2HKO you between Rock Slide and Night Slash, the problem is you only have a 54% chance of doing the same with Psychic. Don't even bother with Infernape or Empoleon, both will kill Froslass.
Elite Four Aaron (Pokémon League, Bug-type): Scizor and Heracross are to be avoided due to having either a Steel-type STAB move (Scizor), or knowing Stone Edge (Heracross). Everything else is doable. Yanmega's measly special defense leaves it open to Ice Beam and even if Vespiquen's Power Gem is a 3HKO if you have leveled in accordance with Cynthia, Ice Beam wins out. Drapion is interesting as despite its type advantage, it lacks a way to hit Froslass super effectively. Aerial Ace 6HKOs at best, bet you didn't see that coming from Froslass. (Ice Beam is a 2HKO)
Elite Four Bertha (Pokémon League, Ground-type): Leave Whiscash to a Grass-type for the sake of convenience. In the event Froslass is your only option however, it's not too bad. At level 58, Froslass wins out with Ice Beam, although it is only a certain 3HKO, in comparison to Earth Power's 0.7% chance to do the same. Gliscor just falls to Ice Beam without getting the chance to do anything, and the same applies to Golem. Unfortunately, Froslass falls just short of being able to OHKO Rhyperior, which promptly follows with 0 Atk Rhyperior Rock Wrecker vs. 0 HP / 0 Def Froslass: 312-368 (186.8 - 220.3%) -- guaranteed OHKO, avoid unless you have an Icicle plate or similar boosting item. It's a somewhat similar story with Hippowdon, although it needs a critical hit to OHKO Froslass with Stone Edge. equip a Charti berry and approach with caution.
Elite Four Flint (Pokémon League, Fire-type): No, use whatever carried you up the waterfall in front of the building here instead. All five of his Pokémon will kill Froslass with their STAB move of choice.
Elite Four Lucian (Pokémon League, Psychic-type): Mr. Mime is only 2HKO'd by uninvested Froslass with Shadow Ball holding a Spooky plate, letting it set up dual screens to ruin your day. However, that's implying you have not invested in special attack, you need 204 evs with a neutral nature and 112 on a positive one to ensure the OHKO (have 145 special attack or more). Espeon hits hard with Shadow Ball, having access to a 2HKO but you do the same with a shot at OHKOing. Given the speed tie, provided you have 158 speed or more, feel free to engage with care. Bronzong 2HKOs with Gyro Ball and even with max investment and a positive nature, Shadow Ball is only a 3HKO without critical hits. You need 172 speed in order to take out Alakazam without running the risk of a critical Psychic OHKO, however Shadow Ball is a certain OHKO with 135 or more special attack with the spooky plate. Gallade is dangerous as Stone Edge comes just shy of OHKOing Froslass, which combined with a high critical hit ratio makes this a dangerous fight. You are likely to outspeed and Shadow Ball is a surefire 2HKO even with its Sitrus berry with max investment and the spooky plate. It's risky but not impossible.
Champion Cynthia (Pokémon League): Spiritomb is a losing battle as while both of Froslass' STAB options have a high chance at 2HKOing, the legion are certain to do so with Dark Pulse. The Icicle plate flips this battle on its head however, giving Froslass the certain KO given its significantly higher speed stat and given what else is to come, you need all the power behind that Ice Beam you can get. Lucario is to be avoided as Stone Edge and Shadow Ball are certain 2HKOs. Froslass is 3HKOing with Thunderbolt in return. The same applies to the Mirror Coat wielding Milotic as Thunderbolt at most does exactly 50%, which spells doom if it decides to counter. Roserade should be outsped and OHKO'd by Ice Beam. Togekiss requires a critical hit to be OHKO'd and Air Slash will do between 42 and 50% in response. However this should not be too big of a problem as Froslass is highly likely to outrun it. Garchomp is a major threat to most teams due to its incredible bulk and power. If you have more than 165 speed however, that threat is instantly vanquished through STAB Ice Beam. Even if it does outspeed, it needs a crit to OHKO Froslass with Stone Edge or a roll with an attack boosting nature, which can be undone with a Charti berry in the case of the later. Still best to be faster though, given Stone Edge's high critical ratio.
Post-Game: The postgame is not kind to Froslass. This becomes blatantly obvious with the number of hard hitting and bulky Pokémon littered across the island, which should be apparent from the double battle in the Battle Area. 80 special attack will not be sufficient in dealing with the challenges ahead, let Froslass retire as a champion and bring in something better suited for the remainder of your journey.
When caught, Snorunt will know Headbutt, Protect, Ice Fang and Crunch. Most of its options is not worth holding off on evolution, although Ice Shard at level 37 may have use in order to pick off faster threats, although Froslass is decently mobile. After evolving, through move relearner it can pick up Ominous Wind for an early Ghost-type option. At level 40, it learns Hail, which complements its ability well, but is unlikely to be of benefit to its teammates. Blizzard, comes long after you get the TM at level 51 and Destiny Bond requires your Pokémon to faint in order for it to work, not worth it.
Through TMs, Froslass gets the vast majority of its coverage options, and its best STAB choices. Ice Beam and Shadow Ball are powerful options that hit a wide range of types hard. Thunderbolt serves as a way to cut through most Water-types, particularly Gyarados. Psychic smashes through Fighting and Poison-type. Water Pulse provides a method for Froslass to deal with Fire and Rock-types in a pinch but these should be avoided normally. In terms of support options, Light Screen, Toxic and Thunder Wave serve as ways for the Yuki-onna to help its team.
Recommended moveset: Ice Beam, Shadow Ball, Thunderbolt/Psychic, Ice Shard/Water Pulse/Thunder Wave/the other move slashed in the third slot.
Steel-types: Given the rather large list of weaknesses Froslass is burdened with as an Ice-type Pokémon, it is reassuring to know that those of the Steel-type pack a resistance to every one of theses besides Fire. Froslass also benefits from their Fighting-type problem, getting free switches as a result of its Ghost-typing as well as providing a fast check to Ground-types.
Water-types: If you are using a Steel-type in order to cover most of Froslass' many weaknesses, that is a third of your team weak to Fire, which despite its rarity in Sinnoh, shows up frequently enough in order for it to be an issue. Combined with the abundance of Water HMs required to progress multiple times throughout the story and you should already have found your solution. Froslass even makes quick work of Grass-types to boot.
Fighting-types: Another potential way to deal with a cluster of Froslass' weaknesses comes in the form of Fighting-types. While they lack the protection against Ghost-type attacks those with a Steel can claim, they also lack the shared Fire-type weaknesses. Froslass also thrives here, handling Flying and Psychic-types troubling the warriors.
Minimum stats are calculated with 0 EVs, IVs of 0, and a hindering nature, if applicable.
Maximum stats are calculated with 252 EVs, IVs of 31, and a helpful nature, if applicable.
What Nature do I want? Modest provides a vital boost to Froslass' attacking power, making several key fights significantly easier to deal with. Timid is also of note, allowing for faster threats to be managed in a safer manner.
At what point in the game should I be evolved? The moment you catch it is ideal, Snorunt is not up to par when you catch it and the few moves of note you miss are redundant with Froslass' learnset.
How good is the Froslass in a Nuzlocke? Overall, it is an average Pokémon. There will be several moments where its offensive presence is simply not up to par without item support and while fast, lacks the support movepool to serve as anything other than an attacker. The questionable typing, with its plethora of common weaknesses makes this line a challenging pick to use. However it does truly come into its own against most of the Elite 4 and Champion. It may have problems getting to the league but once there, it will not disappoint and hey, if Victory Road or the Rival claimed a casualty on your team, it is a solid endgame replacement.