Editor’s Note: Dan Stillman is a meteorologist and co-founder for The Washington Post’s Capital Weather Gang. The opinions expressed in this commentary are his own. View more opinion at CNN.

CNN  — 

Meteorologists learned long ago that an accurate forecast or severe weather warning is useless if it doesn’t reach its intended audience. The same is true for public health guidance.

In today’s world, the most effective way to reach those who might be in harm’s way, no matter what type of hazard it may be, is through mobile phones. Those who have received a Wireless Emergency Alert (WEA) know it is almost impossible to ignore due to the blaring alarm tone that accompanies the text message. These alerts, which can target cell phones in specific geographic areas, are typically used for severe weather or Amber alerts.

With the number of Covid-19 cases, hospitalizations and deaths on the rise, state and local authorities in Maryland, Pennsylvania, Utah, Massachusetts, New Mexico, Rhode Island, Alaska, and California have recently sent WEAs to communicate vital information about mask-wearing, social distancing, testing, and hand washing. Yet this patchwork approach has only reached a small fraction of the total US population.

The most powerful and far-reaching feature of the WEA system – the ability to send a nationwide “Presidential Alert” in a time of crisis – has never been used (other than a test run in 2018) since the system was launched by the Federal Emergency Management Agency (FEMA) in 2012. The FEMA website states that presidential alerts “are a special class of alerts only sent during a national emergency.” Unlike other types of WEAs, users cannot opt out of these alerts.

Given that Covid-19 is one of the worst national emergencies in modern history, having already killed more than 295,000 Americans, President-elect Joe Biden should prepare to utilize the WEA system on Day 1. Biden already has shared his intent to ask all Americans to wear masks for his first 100 days in office, and a presidential alert would help convey the importance of taking precautions. When the Covid-19 vaccine is more widely available, the alert system also can be an effective way to communicate critical information about where to get one and why it’s important.

Several countries have sent nationwide text alerts on Covid-19 including the United Kingdom, New Zealand, Australia and South Korea.

Some might wonder why WEAs are necessary at all, with so many readily available news sources. For one, people are easily overwhelmed by the sheer volume of information online. Secondly, while many people follow the news or check social media every day, there are millions of Americans who do not, whether that’s by choice or because of the nature of their jobs or daily routines.

During an emergency or crisis, the WEA system offers a direct line of communication to every American with a cellphone. It also offers an opportunity to cut through the noise – and misinformation – that can limit the reach and effectiveness of important public safety messages.

The National Weather Service has made particularly good use of WEAs, recognizing that even in a well-publicized severe weather situation, not everyone is tuned into a trusted news source or weather app at all times. The WEA system is employed “because it is able to nearly instantaneously reach anyone in a designated area…without the need for prior registration,” according to a Department of Homeland Security (DHS) report.

Some might think WEAs should be reserved only for sudden emergencies like a tornado or missile attack. But the timeframe of the emergency is not part of the criteria for sending a WEA. And in fact a report published by DHS found that WEAs may actually be suited better for more slowly evolving emergencies (like a pandemic) “where the descriptions of the emergency events and the recommended preparedness actions are simple and relatively unchanging.”

Get our free weekly newsletter

  • Sign up for CNN Opinion’s new newsletter.
  • Join us on Twitter and Facebook

    In the case of Covid-19, a single presidential alert stressing the importance of wearing a mask, social distancing, and washing hands could save thousands of lives before vaccines are widely available later next year. The Biden Administration, in consultation with public health experts and communication specialists, should start crafting an alert to be issued on Inauguration Day or shortly thereafter.

    Sending such an alert would broadcast a lifesaving message to the vast majority of Americans, and also serve as a symbolic gesture to the nation – and world – that the US government is finally treating this virus as a national emergency.