Yes, it was shivering. Only happened on the handles and not the body of the pieces. The handles were very rounded -- one was shaped like a chili pepper -- but I guess they could have cooled faster than the rest of the pot. Thanks for your help.
do you mean that razor sharp little bits of fired glaze popped off after the glaze firing? if so, that is a condition called shivering. it comes about because the clay body and fired glaze have different coefficients of expansion. as the pieces are cooling down in the kiln the clay shrinks more than the glaze and the glaze no longer fits on the clay. little shards of glaze pop off the pot to relieve the pressure. there is not much you can do about it except to alter the recipes of your glaze and/or clay (but it sounds like you are using pre-mixed clay and glaze) or to use a different clay or glaze.
i have a similar problem with my white glaze and terra cotta body, but fortunately it is not a combination i use too often. if i can keep the glaze a bit thin then i seem to have a better chance of my piece coming out ok. also, your form might have something to do with it - shivering tends to occur at sharp edges on lips and handles. if you make those edges a little fuller and rounder it might have a positive effect.