--Updated 9/9/17, noon EST--

Hurricane Irma as it bears down on the Florida coast / NOAA

Four days after Hurricane Irma became the largest storm ever recorded in the Atlantic, Governor Rick Scott announced, "the storm is here," prompting one of the largest emergency evacuation in American history.

Friday night, Irma crashed into Cuba as a Category 5 hurricane. That's the most devastating category defined by the Saffir-Simpson Scale. For context, Hurricane Sandy was a Category 1 when it hit New Jersey, and Category 5 storms in general are 500 times more destructive.

Gridlock during the largest emergency evacuation in state history/ Erik S Lesser EPA

On Wednesday, Hurricane Irma made landfall on the islands of the northeastern Caribbean, destroying 95% of the buildings on Barbuda and causing at least 20 deaths so far. On the French Island of St Martin, winds were recorded as high as 185 miles per hour with a storm surge 20 feet above sea level.

As concerned citizens around the country helplessly wait for Irma's inevitable destruction, it is important to understand how to donate effectively at all stages of a natural disaster like Irma.

Before Irma: Blood Donations

The most critical time for blood donations is before the storm so that the supply for hospitals is up to par during and after Irma breaks ground. The blood supply in Texas was interrupted for several days as Hurricane Harvey made transportation impossible.

In response to Harvey, Florida-based, One Blood depleted a portion of it's supply, sending 300 units to restock blood centers in Texas. However, this generosity has left their blood banks in critical need of donations as Irma approaches.

Centers across the country have sent blood to replenish blood banks in Houston in the aftermath of the hurricane, and with Irma on the way, donating blood is a great way to help out even if you don't live in Florida. They are in urgent need of Type 0 positive and O negative in particular, so find a blood drive near you here.

Immediate Response: Send Money not Goods

As the extent of Irma's wrath becomes clear, people across the country will be compelled to help out in any way they can. At this stage of the response effort, cash donations are almost always preferred over the used clothing, blankets and stuffed animals often sent to disaster areas by well meaning donors.

This outpouring of support has tremendous capacity to impact the victims of natural disasters, but in this phase of the recovery cash is king. In response to Hurricane Harvey, Derrick Chubbs, president of the Central Texas Food Bank, urges people to, "donate funds, because we can use those to purchase exactly the type of disaster relief supplies that are going to be most helpful."

8,000 boxes of donated clothes ruined by flooding in Harvey/ Source Goodwill.

The unfortunate reality is that boxes of clothes must be separated by size and type; bags of groceries must be inspected and individually checked for expiration dates by volunteers. After a hurricane, relief agencies don't have the storage capacity for unsorted donations and boxes of used clothing can impede cleanup efforts. At this stage of the response effort, triaging physical donations uses up valuable volunteer resources and often only serves to clutter relief areas.

There is a time and a place for in-kind donations but it is important to know that you are supplying something people actually need. It might be weeks after Irma before we know which items are in urgent need. So after the first responders have rescued people from the wreckage, and victims have been relocated to temporary shelters, contact the local FEMA representatives and ask what specific items they need.

Long-Term Support is Vital

Recovery from Hurricane Irma will be a long-term event, and sustained private support will be essential for complete recovery.

Bob Ottenhoff founded the Center for Disaster Philanthropy after Hurricane Katrina in 2005, specifically to encourage effective giving. Ottenhoff's research explores the life cycle of disaster philanthropy and in response to Hurricane Harvey, he explains that each phase of the disaster has different associated needs.

Whereas an organization like the Team Rubicon is well equipped to provide immediate assistance like flood rescue, and clearing debris, they are not in the business of medical treatment or rebuilding neighborhoods. (NPR)

Irma's Caribbean devastation shows a glimpse of whats coming for Florida / CNN.

Though they are the national catch-all for disaster fundraising, The Red Cross received criticism from the international community after it raised $488 million for the Haitian earthquake, but failed to spend even a third of the money 2 years later. What people failed to recognize is that there's only so much money that can be forced through the emergency phase of disaster response. Haiti would likely be in better shape today if that money was allocated to other nonprofits at other phases of the recovery effort.

Historically, people respond immediately to disasters like Hurricane Irma but tend to he lose interest in the weeks, months and years ahead. You can combat this by pledging monthly support to organizations like Habitat for Humanity Florida, which will be heavily involved in the long-term Irma recovery effort.

As the media cycle moves on and the donations dwindle, the victims of Irma and Harvey will have to return home and begin to rebuild their lives. Ottenhoff suggest that people should give some money now for immediate relief, but set aside charitable dollars for later, when they can be targeted to have an even greater impact.

Other Ways to Help

One way to combat this trend is to download GiveTide, a mobile app that rounds up spare change on electronic purchases for charity. Your spare change will gather on the app in the days and weeks following a disaster, and by the time it becomes clear what organizations need the money most, you will have a pool of spare change to donate with a single tap. Three organizations to consider are:

Direct Relief: One of the most effective organization in the emergency preparedness stage of the disaster response, Direct Relief has been tracking Irma for weeks. They've already dispersed strategic medical equipment across the Caribbean and Florida in preparation for the storm.

Team Rubicon: Founded by a former Marine sniper, they have built their reputation responding to disasters with the skills and experiences of military veterans. TR rapidly deploys first responders and disaster response teams across the country and the world. They brought a powerful team of Veteran volunteers to Houston and they will likely be some of the first boots on the ground in Florida as well.





Habitat for Humanity Florida: They played a big role in rebuilding houses after Hurricane Katrina, and are poised to bring a national network of volunteers to rebuild homes after Irma. Habitat will be rebuilding in Florida long after the response teams move on and have the community connections to implement a sucessful relief effort.