Hurricane Harvey made landfall Friday as a Category 4 storm, slamming Texas with brutal winds and severe flooding, leaving Houston underwater and millions of residents in need of aid. Here are some ways you can help.

Red Cross

Texas Gov. Greg Abbott recommended that those who want to help victims should donate to the American Red Cross, which he called a “tremendous asset.” A number of other organizations at the national, state and local levels will provide vital assistance to residents in the coming days, weeks and months.

Local and national relief organizations

The Salvation Army, Save the Children, Southern Baptist Disaster Relief, Heart to Heart and Samaritan’s Purse are all on the ground in devastated areas and seeking donations to continue their response efforts. Texas Diaper Bank is sending out disaster relief kits to those affected.

Food banks

Feeding Texas is a statewide network of food banks, and Houston Press has compiled a list of food banks serving the area hardest hit by Harvey. That list includes Houston Food Bank, Galveston County Food Bank, Food Bank of Corpus Christi and San Antonio Food Bank, among others.

Pets

To help nonhuman Texas residents, animal welfare organizations will be focused on rescuing, sheltering and rehoming pets. The Humane Society and the SPCA of Texas and their affiliated shelters will need money, supplies, food and foster volunteers.

Blood

Blood donations can be made through the American Red Cross, and Carter BloodCare, We Are Blood and the South Texas Blood & Tissue Center are all Texas-based organizations sure to be seeking increased donations.

Other relief efforts

Airbnb has set up an Urgent Accommodations page, allowing evacuees to find a place to stay for free with the help of those able to offer their space at no charge.

A list of individual crowdfunding campaigns related to the hurricane can be found at GoFundMe’s Hurricane Harvey Relief page. GlobalGiving, another crowdfunding site, is aiming to raise $2 million for a relief fund.

Most of the above organizations have volunteer opportunities available as well.

“I just woke up an hour ago and stepped out of the bed into ankle-deep water,” said Jake Lewis, who was visiting Houston for work and found himself stranded in a hotel Sunday morning.

“I’m not going to go out there and get in a bind,” he told CNN. “It’s been madness around here. The water keeps rising.”

“What we’re seeing is the most devastating flood event in Houston’s recorded history. We’re seeing levels of rainfall that are unprecedented,” said Steve Bowen, chief meteorologist at reinsurance firm Aon Benfield.

Ify Echetebu took to Instagram to post photos of her aunt’s house in Dickinson, Texas, southeast of Houston.

The water had risen to her waist, she said.

“National Guard is only responding to emergencies and 911 said do not call them.”