Demonstrators gathered Saturday to embark on a 120-mile journey from Ferguson to Jefferson City, the state capital of Missouri, Reuters reported. About 100 people were expected to begin the first leg of the march being held to protest the police-involved shooting death of Michael Brown, 18, in August.

The march was organized by the National Association for the Advancement of Colored People. More people will join the march as it goes on. Headquartered in Baltimore, the NAACP anticipates about 1,000 people will participate in the final leg of what it is calling the Journey for Justice.

“We are resolute and excited to get started and moving forward in something that's positive, a nonviolent demonstration toward criminal justice reform and police reform," NAACP staff member Jamiah Adams told Reuters Saturday. The march began at midday near the Canfield Green Apartments, the same complex where Brown was killed.

Although AccuWeather is currently reporting the air temperature as being in the 60s in the area, NAACP staff members have warned marchers to prepare for a cold front moving in this week, when the overnight temperature could drop into the 20s.

Nationwide outrage was fueled last Monday, when a St. Louis County grand jury decided not to indict Darren Wilson, 28, a member of the Ferguson Police Department, for shooting and killing Brown, a teen who had robbed a convenience store and allegedly reached for Wilson’s gun during a scuffle. Demonstrations subsequently broke out in several urban areas across the country.

Some of the protests on Black Friday were peaceful, but at least 15 arrests were made after hundreds of people shut down three malls in the St. Louis area.