UPDATE 7/11 6:00 a.m.
According to the Army, the aircraft has a wingspan of 20 feet and can hold up to 460 pounds. It's used to provide "reconnaissance, surveillance, target acquisition, and force protection."
The crash sparked a brush fire. Crews from the Army Wildland Fire Department, Federal Fire and Honolulu Fire Department all responded to the scene.
It happened in an isolated area, so crews used helicopters to assist.
As of Wednesday night, about a quarter acre of land was burned.

No injuries were reported, and thankfully no other aircraft were in the area when the drone crashed.
UPDATE 10:00 P.M.
The Honolulu Fire Department reports that the downed aircraft in mountains above Kunia is now 90% contained.
It is still smoldering at this time but has been handed over to DOFAW.
This story will be updated as details become available.
UPDATE 7/10 7 P.M. 
The 25th Infantry Division released the following information regarding the crash Wednesday afternoon that sparked a brush fire in mountains above Kunia.
According to the Division, an RQ-7 Shadow Tactical Unmanned Aircraft System operated by the 25th Infantry Division crashed during a training flight in the Waianae Mountain Range adjacent to Schofield Barracks at 3:30 p.m. Wednesday.

The Army’s Wildland Fire Department with the Federal Fire and Honolulu Fire Departments have responded and are currently working to extinguish the resulting brush fire, as well as conduct an assessment of the area.

Additionally, the 25th Infantry Division have dispatched aircraft to perform an aerial assessment of the area and are supporting with fire suppression.

No personnel were injured and no other aircraft were in the area at the time of the incident.

At this time, the cause of the incident is unknown, more information will be released pending the results of the investigation.

UPDATE 7/10 5:19 P.M. :
A total of 5 fire units equipped with 9 firefighters are responding to the brush fire that they say is occurring in the mountains above Kunia.
The firefighters were dispatched at 3:47 p.m. and arrived on scene at 4:03 p.m.
An HPD helicopter is joining in the effort.
An official from the 25th Infantry Division has confirmed that an unmanned aircraft belonging to the division has crashed Wednesday afternoon.
The crash has sparked a brush fire in the Schofield area where Honolulu firefighters are currently responding.
The U.S. Army has dispatched teams to conduct an assessment.