You may see them on your drive to work, while walking your dog at the park, or at intersections with crumpled signs requesting help. They are people without homes, sometimes even without shelter for the night.

There are more than half a million people homeless in the U.S. in any 12-month period, and almost 200,000 of them sleep without shelter on any given night.

“I think COVID made people more aware of the issue of homelessness,” says Steve Berg, vice president for programs and policy at the National Alliance to End Homelessness in Washington, DC. “Everyone was told to stay home during the pandemic and people became acutely aware of those who couldn’t because they didn’t have a place to live.”

How does someone go from working and having a place to call home to living on the streets? It’s not always easy to tell. In some cases, bad decisions may play a part. But more often, circumstances take on a life of their own.

“People are often too quick to point to individual decisions as the reason for homelessness versus structural issues,” says Carolina Reid, an associate professor of city and regional planning at the University of California, Berkeley, and research adviser for the Terner Center for Housing Innovation. Those structural issues include low wages, lack of affordable housing, lack of jobs, and deep-seated patterns of racism that are baked into our society and its infrastructure, she says. Other issues that can lead to people living without a home include:

But it’s not always easy to know how to react in a compassionate way to people living on the street. You may want to help but find it hard to engage directly with someone you don’t know. And it’s true that there are higher rates of mental illness and substance abuse in the population of people who are homeless. That can make it harder as well. But, say experts, there are things you can do to help in a compassionate way:

Acknowledge them as people first: “People who are homeless” is the term many experts suggest. It may seem like a small thing, but it acknowledges that these are human beings first. Homelessness is simply a description of their circumstances. You can also use other phrases, like “people without shelter,” or “neighbors in need.”

Know the root causes: It can be tempting to think a person experiencing homelessness is on the streets because of bad decisions. But the reality can be more complex. Many may find themselves without shelter because of issues beyond their control.

“Everyone makes poor choices, but those of us with a strong network can often rebound,” says Reid. Knowledge of the many reasons someone might be without a place to lay their head at night can be a good first step to making a difference. You can learn more about the roots of homelessness at advocacy organizations like the National Alliance to End Homelessness.

Donate time: Look for organizations in your area that are doing something to serve those in need – whether faith-based or secular nonprofit.

“These organizations rely heavily on donations, whether it’s time or money, and they all have been stressed by COVID,” says Berg. Since the pandemic, many shelters have limited hands-on tasks such as serving food. Find out if you can help virtually. Small tasks like helping with mailings, phone calls, social media, or even making hygiene kits are other ways to lend a hand.

Donate money: Donating to homeless service organizations can help with everything from a hot meal or shower to providing services such as drug and alcohol counseling and job training. Nonprofits are making it easier to donate, too. Many offer online giving or the option to set up automatic monthly or quarterly contributions.

Donate stuff: Shelters need canned food, gently used clothing, and personal care items like soap, deodorant, and feminine products. “These organizations need donations, but they need support around the year, not just at holidays,” says Tracy Porter, founder of God’s Hands and Feet Global Ministry in Pasadena, CA. Porter, who was once homeless, now devotes herself to helping people in the same community.

For people living on the streets, blankets and coats are helpful as temperatures drop at night, says Porter. And don’t forget about the little people. Sadly, younger people make up a big chunk of those living without shelter. Consider donating backpacks and baby supplies. Many organizations will post their needs list online, or you can call to check.

Call the mayor: The mayor’s office is used to hearing from concerned citizens about a variety of topics. If homelessness is a big one for you, do not hesitate to reach out. Ask them to push forward the ideas that are proven to make a difference. Visit your mayor’s office website to learn what is planned in your area.

Be a friend: If you feel safe and you are so inclined, consider talking to people you run into who are unhoused. Ask them what they need – food, money, water. It’s possible that money may be used for drugs or alcohol, but the risk may not be as high as you think. In one study, those given cash moved into housing faster and spent most of their money on food, medicine, and personal care items.

Call the experts: Some cities have decided that law enforcement is not always the best response to homeless people – particularly those with a mental illness. The police focus on crime, and homelessness is not a crime. Find out if your city has a phone number for mental health experts who can respond if you see someone in need of help. You can also try local advocacy organizations that are experienced with populations that lack shelter. They may be able to point you to more resources.

Consider fostering a child: Children in foster care are more likely to become homeless. Some have aged out of the system with no support. Others continue to battle issues that prevent a stable life. Becoming a foster parent can break this cycle.

Write your member of Congress: Homelessness is a big issue, and that means big spending may be required to fix it. Consider reaching out to your local member of Congress via www.house.gov to find out who is responsible for bills and spending related to homelessness and do what you can to support them.

Be patient: Experts like Reid and others suggest we all have patience and empathy with the system. “This issue was created over decades and won’t change overnight,” she says. Nonprofits are on the front lines, and there are things you can do, too.