EMB ERJ 145 ER/LR
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
ATC Issue All Types; Conflict NMAC
Flight Crew Took Evasive Action
Human Factors; Procedure
NMAC We were cleared for takeoff runway 31L at HIO by the tower controller.  We were not advised of any specific traffic to the West of the airport that might be in our departure path (though a general glider advisory was on the ATIS).   The tower may not have been aware of any specific traffic.  We were climbing on the CHISM3 departure; I was hand flying the aircraft and following the flight director in LNAV and IAS mode at 200 knots.  At about 2500 feet the flight director commanded a left turn past HETAT intersection.  As we were making the turn through about a heading of 240 degrees I caught a glimpse of an aircraft emerging from behind the center windscreen post.  It was slightly above us (approximately 100 feet) and very close to us laterally; flying perpendicular to us traveling from left to right. I realized our current trajectory (the left turn) would cause us to clear the traffic so I continued the climb (too late to level off) and the turn.  The aircraft passed about 200-300 feet from us laterally at approximately the same altitude.  At that point I identified the aircraft as a glider (t-tail) and noticed that it was under tow.  (The tow aircraft being high-wing single-engine further to the right of our flight path).  Neither aircraft made any evasive maneuver so I am uncertain if they saw us.  The entire incident happened within a matter of seconds.At this point I looked at the TCAS to see why we didn't get a resolution advisory and noticed that neither aircraft appeared on our display at all (not even as a 'no bearing' target).  The TCAS had been tested prior to flight and was displaying other aircraft at the time of the incident.  I then asked the Captain if he had noticed the traffic and he said he never saw it.  We were with Portland approach control at that point and didn't have time to call the tower to query them.  Following the flight; two passengers asked me if we had seen 'that glider.'  I told them we had seen it and were able to avoid it.  My concern is why such aircraft operations were occurring so close to the departure path used by high performance aircraft and why there were apparently no transponders and no communications with ATC being employed by those aircraft. Glider operations should communicate their positions to tower when operating so close to their airspace. Glider operations should alter their patterns/altitudes to avoid heavy IFR and high performance departure areas.  ATC should issue alternate departure procedures when gliders are in the area.  Flight crews should brief heightened awareness and visual scanning when glider operations are advertised on ATIS.  Flight crews should not become overly dependent upon TCAS to avoid all potential traffic conflicts.
EMB-145 Captain reported an NMAC with a glider under tow during departure from HIO.