PLT OF SMA FAILS TO FLY DEP PROC ON IMC DEP FROM COE.

Narrative

I FILED AN IFR FLT PLAN IN IMC FROM COEUR D'ALENE ARPT; ID; TO LEWISTON; ID. THE CTLR READ OFF MY CLRNC; GIVING ME THE DEPARTING FREQ; SQUAWK CODE; THE DIRECTIVE TO CLB TO AND MAINTAIN 7000 FT; AND TO EXPECT RADAR VECTORS TO LEWISTON. SHE DID NOT MENTION A DEP PROC. I ERRONEOUSLY ASSUMED THERE WAS NONE WHEN; IN FACT; THERE WAS. I TOOK OFF ON RWY 5 AND WAS ALMOST IMMEDIATELY IMC. I STAYED IMC AND REALIZED I WAS HEADING INTO HIGHER TERRAIN. I BEGAN ASKING THE CTLR IF SHE HAD ME ON RADAR. SHE REPLIED THAT SHE DID NOT; AND WHEN I ASKED HER HOW LONG IT WOULD BE; SHE WISELY SUSPECTED SOMETHING AMISS AND INQUIRED IF I WAS EXECUTING THE PUBLISHED DEP PROC. WHEN I TOLD HER I WAS NOT AND THAT I WAS ON RWY HDG; SHE TURNED ME FROM 50 DEGS TO A SW HDG; AWAY FROM HIGHER TERRAIN. A SHORT TIME LATER; I CAME UP ON RADAR AND THE FLT WAS COMPLETED WITHOUT INCIDENT. MY ERROR WAS IN ASSUMING THERE WAS NO DEP PROC WHEN; IN FACT THERE WAS IN MY BOOK OF APCH PLATES. I NOW REALIZE THAT IN THE ABSENCE OF INSTRUCTIONS TO THE CONTRARY; DEP ON AN IFR CLRNC FROM AN UNCTLED ARPT MANDATES SUCH A PROC BE FOLLOWED.