you have to go through a few things first.....
. Have you gone to the lakes yet?
. Did you save the lake pokemon from the bad guys place
If you had done all of that you are possibly have missed the place to go once you are out side for the second time when its really i mean REALLY snowy there should be a a ditch where there is a cave door skip it and keep going straight and you will get to the end there is a rock climb in front and to your left go left from there is is pretty simple just follow the path and go where ever it leads you
Sorry if this is what i remember of the game i have not played for 3 years
You can find Cyrus at mount coronet near the end of the game
Pokemon is lame..
hes right in front of palkia
After releasing the three Pokemon of the lakes, Cyrus goes to the top of Mt. Coronet
you find dialga in mount coronet
You can find it: -Mt. Coronet -Trophy garden
You will find them in the spear pillar.
in caves and mountains, especially mt. coronet
in the light house
get the Pokemon platinum guide book
we get him in the sky pillar where palkia appears
In Pokémon Pearl, Chimecho can be found in Mt. Coronet and in the Spring Path.