Rain of Ice Daggers

Area 
Ice Daggers rain from the sky onto the area, causing 1d-2 impaling damage per second to all within it. Characters and creatures under the Rain of Ice Daggers take damage on their own turns; if less than an entire second is spent in the affected area, damage is halved (round down). 
The spell can only be cast out of doors. Armor protects in the usual fashion. A shield with a DB of 2 or better can be held overhead to block the ice, but it may take damage (p. B484). This requires two hands and a Ready action, and succeeds automatically in protecting the character once the shield is readied upwards, but this unreadies the shield from its normal protective functions! 
Inanimate objects such as buildings protect with their DR.

Duration: 1 minute. 
Base cost: 1 (minimum 2). For double base cost, the Rain of Ice Daggers does 1d per second! 
Prerequisites: Magery 2, Hail, and Ice Dagger.

Item 
Staff. Usable only by mages.  
Cost to create: 800 energy and a $1,000 sapphire.