Blizzard

Summons massive shards of ice to destroy your enemies.

Blizzard is a Sorceress Cold skill (level 24, requires Frost Nova and Glacial Spike) and the prerequisite of Frozen Orb. It is an area: for a few seconds, ice shards rain on a circle where you cast it, and every shard that lands on a monster damages and chills it. Two numbers decide it: the damage of one shard, 570–619 at level 20 before synergies, and the 1.8-second casting delay that sets how often you can cast it.

The numbers

The damage is per shard. It comes from EMin 45 and EMax 75 with HitShift 8: 45–75 at level 1. The minimum then grows +15 a level to level 8, +30 to 16, +45 to 22, +55 to 28 and +65 a level past that; the maximum grows +16, +31, +46, +56 and +66 over the same brackets. That is 210–249 at level 10, 570–619 at level 20 and 1,120–1,179 at level 30. The line reads lvl, so +skills count, and the brackets steepen all the way out.

Mana is 23 at level 1 and 1 more a level (mana 23, lvlmana 1, manashift 8): 32 at level 10, 42 at level 20, 52 at level 30.

Four numbers never change and are left out of the table. The casting delay is localdelay 45 frames, 1.8 seconds. The radius is Param1 7 (the table's "Radius for Area of Effect", calc1), which is 4.67 yards. The spawn rate is Param3 4 ("Missile Spawn Rate", calc2): a shard every 4 frames. The cold length is ELen 100 with no per-level columns, 4 seconds on every shard. The tooltip's duration line reads the range of the "blizzardcenter" missile, which the repo's bank cannot compute; the Basin's page prints it as 4 seconds.

How it works

Blizzard places a "blizzardcenter" missile where you click, anywhere in line of sight on the screen; the Basin's page classes it as a medium-range area-of-effect multi-missile cast. From the Basin: a shard falls every four frames (0.16 seconds) somewhere within the radius for the duration, so one cast rains 25 shards in a somewhat random pattern. Shards are size 2, so one shard can hit more than one target, but a stationary size-3 target under the centre is normally hit by only 4 of the 25, and a size-2 target by 3. Each shard is cold damage, reduced by the target's cold resistance, see Dealing Elemental Damage and Resistances and Immunities; there is no attack roll. Every shard that lands chills for 4 seconds, divided by the difficulty's cold divisor in Nightmare and Hell, see Chill and Freeze.

The casting delay is 45 frames, and the Basin's page says that in D2R it is local: it locks Blizzard, not your other skills. The Basin's way to count damage a second: shards that hit × duration ÷ cast rate, where the cast rate is the delay plus the cast's action frame, 45 + 4 to 7 frames depending on Faster Cast Rate.

Only a few of the 25 shards hit any one monster; the number on the tooltip is one shard, and a target that walks out of the circle takes fewer.

Synergies and +skills

• Ice Bolt: +5% cold damage per level, Ice Blast: +5% cold damage per level and Glacial Spike: +5% cold damage per level (skills.txt Param8 = 5; the calc reads each skill's blvl, hard points only).
• Blizzard in turn feeds Ice Bolt (+15% a hard point), Frost Nova (+10%), Ice Blast (+8%) and Glacial Spike (+3% freeze length).
• +skills raise the shard damage (lvl); the percentages, the radius, the delay and the cold length do not move with +skills.
• Cold Mastery lowers the target's cold resistance and so raises what lands.

Against players

A player's hit on another player is cut to 17% of its value (difficultylevels.txt PlayerDamagePercentVSPlayer) before anything else, see Player versus Player. The Basin's page gives no other rule for Blizzard against players.

Build notes

• The three synergies are 5% each, 60 hard points for +300%; they are the prerequisites' own damage too, and Ice Bolt at 3 mana and Glacial Spike's freeze come with them.
• The brackets reach +65 and +66 a level past 28, so +skills gear is worth more here than on any flat-bracket cold skill: level 30 is 1,120–1,179 a shard, nearly double level 20.
• The delay is the cap on casts, not Faster Cast Rate: by the Basin's count a cast is 49 to 52 frames, 45 of delay plus 4 to 7 of action, so all the cast rate in the game saves 3 frames a Blizzard.