Apricots and cherries can have a fairly short lifespan in many climate zones in California due to a disease called Eutypa.  This disease is able to invade through pruning wounds especially during the wet winter months.  This disease causes limbs or twigs to wilt and die suddenly in late spring or summer with the leaves still attached. 
The bark may appear dark with an amber colored gumming on the branches.  

To combate that the disease and reduce the potential for Eutypa to infect trees, you should begin pruning your apricot and cherry trees during the later part of summer and early fall at least 4-6 weeks prior to rainfall.  However, realize that you may be opening your trees to sunburn with summer pruning so be...