(CNN) -- Much of Moore, Oklahoma, which is just outside of Oklahoma City, is now a devastated pile of rubble.
The search and rescue mission continues after a massive tornado touched down Monday afternoon. CNN affiliate KFOR reported that at one time, the tornado was estimated to be at least 2 miles wide, and the National Weather Service is also saying the scale of the tornado is at least EF4. This is the second most severe classification of tornado.
It is clear the days ahead are grave for the people of Oklahoma and the need for help will be immense.
Many unaffected viewers want to help. How can you donate?
Text STORM to 80888 for The Salvation Army USA.
Text REDCROSS to 90999 $10 donations, or
FOOD to 32333 for Regional Food Bank of Oklahoma.
There are several organizations already mobilizing on the ground in Moore, and you can help as well through these groups:
The Red Cross
The Red Cross of Oklahoma has activated its safe and well website for those who are trying to reconnect with loved ones. Red Cross officials and volunteers are also beginning to open shelters. The first is at St. Andrews Church. You can help their efforts by donating to the Red Cross online or by texting REDCROSS to 90999.
The Salvation Army
The Salvation Army has also jumped into action. It's in multiple locations throughout cities in Oklahoma providing food, hydration and emotional support to first responders and storm survivors. You can contribute to the Salvation Army by calling 1-800-SAL-ARMY (1-800-725-2769), online on their website, by texting "STORM" to 80888 to make an automatic $10 donation or by mail:
The Salvation Army PO Box 12600 Oklahoma City, OK 73157
Feeding America is responding by providing food, water and supplies to the residents of the devastated towns in Oklahoma. The group will continue to assess the need on the ground for more assistance as recovery efforts continue.
Samaritan's Purse deployed a group of staff members to travel from its North Carolina headquarters to head to Oklahoma with a Disaster Relief Unit. The unit is a tractor trailer stocked with emergency supplies and equipment.
Global health and disaster relief nonprofit AmeriCares is also mobilizing a team to help in Oklahoma. Its emergency response team is headed to the region to coordinate deliveries of relief supplies and medical aid for survivors. The team is expected to arrive by morning.
Team Rubicon, a group of military veterans who respond to disaster, have issued the call to members and is heading to the region. By Tuesday morning, initial assessment teams will be on the ground, and they will then mobilize a full response to help the people affected by these storms.