The Army wants to conduct a test next winter to determine whether soldiers can fire rockets at a Joint Base Lewis-McChord training area without overly disturbing South Sound residents.
Officials are advancing a proposal to launch 27 training rounds over three days from a range between Lacey and DuPont to gauge how civilian communities might respond to more frequent firing of a weapon called High Mobility Artillery Rocket System (HiMARS).
The rockets have the potential to create a sonic boom and likely will be more noticeable to residents than the howitzer cannons that currently use JBLM artillery training areas.
JBLM plans to host an open house Thursday for residents with questions about the proposal. It begins at 6 p.m. at Eagles Pride Golf Course off Interstate 5, Exit 116 near DuPont. Residents have until Aug. 25 to submit comments on the plan.
JBLM has two artillery battalions that train to fire HiMARS in combat. Soldiers in the units are required to practice launching the rockets at least twice a year to be considered ready to join a deployment.
The two battalions regularly travel to the Yakima Training Center in Central Washington to test the weapons. JBLM would like to give them an alternative that could allow them to train closer to home without incurring about $227,000 in travel expenses for movements of Army vehicles to Yakima.
The Army has considered implementation of HiMARS training in the South Sound for several years.
The Nisqually Reservation is the closest community to the firing range and likely would experience the loudest noises. The Army showed an earlier proposal to the tribe in 2008 and brought tribal members to a HiMARS firing in Yakima in 2009.
The Army also released a study that would have allowed HiMARS firing at JBLM in 2010, but shelved it because of community concerns about noise.
Since then, the has Army updated its noise models for training at JBLM. The latest attempt includes newer information.
JBLM’s HiMARS battalions have deployed several times to Iraq, Afghanistan and other nations that are allied with American forces and developing their own artillery units.
The Army environmental assessment is not a study of a permanent plan to add HiMARS training to JBLM. It looks only at the proposed three-day test.
It notes that noise generated by the test rounds could exceed 130 decibels — louder than what someone would hear from a jet flying 1,000 feet above ground — in the direct path from the firing point to the impact area.
Noise could approach 115 decibels in the Nisqually Reservation and along the east side of JBLM.
The sound could startle mammals, cause birds to adjust flight patterns and possibly disrupt fish hatcheries, according to the study.
Soldiers would not fire actual rockets in the South Sound. They’d use training rounds. The Army also plans to minimize a potential fire risk by clearing an acre of forestland near the launch point.
Residents most often call JBLM with concerns about noise during artillery training events. Audible helicopter training also been a concern for civilian communities since the Army began expanding its aviation units at JBLM during the Iraq War.