I've always found the master destruction spells a bit underwhelming.  They take time to cast, exposing the weak side to the baddies' cheap interrupting shots. Blizzard and Fire Storm are difficult to time correctly, while there are no aimed concentration master spells for the respective elements to target far enemies. The most functional master spell was always lightning storm, but I always felt that such a powerful beam should leave some trace of its passage - besides the electrocuted corpses of the baddies.
This mod introduces four new spells equally divided between frost and fire elements, that can be channeled and target far enemies. 
This way your pyro or crio elemental mage will have a repertoire in the master tier in their own element.

Dragonfire: a stream of white-hot lava that leaves a trail of hazardous flames wherever it explodes
Bora: a glacial stream that explodes on impact and leaves a wall of ice in its path
Lightning storm (vanilla reworked): now there will be walls of storms where the beam hits
Fire Blast: unleash a relentless barrage of fireballs
Frozen Volley: impale enemies with multiple ice spears

All spells can be cast with one hand (therefore even the visual effect will be mixed if casting two different elements), the casting time is lowered and the player character will be able to move while casting.

I also decided to add radial explosive spells. Sometimes you find yourself surrounded by enemies or chased closely. Solutions? Backpedal while casting flimsy flames? None functional. Mages seem to be unable to functionally project magicka in a radius unless they concentrate for 3 seconds and are masters. Radial explosive spells will fulfill this role: damage will be dealt in a radius around the player character to anyone who was foolish enough to close the distance. The new three spells are elemental and balanced to be adept level.

This file overwrites Lightning Storm spell and magic effect records, and the Master and Adept spell tome leveled lists.