Thread by @nsj

While some of us are gathered here and online for #NWAS22, I wanted to kick off a conversation about how we use purple aka magenta aka fuchsia, especially in short-fuse weather warning graphics.

I'm concerned we're backing ourselves into a corner we don't want to be in.

1/

More than a few presentations so far this week have included images or video clips of tornado warnings or other short-fuse events (e.g. TOR or FF emergencies) using purple (or fuchsia or magenta, but I'll stick with purple for simplicity) as the outline or fill color.

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This is a marked changed from 10-15 years ago, when there was near-universal agreement on how we displayed tornado warnings: A bright, in your face, attention-grabbing red color. And that was for good reason: Red means stop, this is important, this is dangerous, etc.

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In some cases, we've backed ourselves into something of a corner with the advent of tornado emergencies (in many ways a "super tornado warning") as well as tags to allow us to differentiate warnings where the tornado has been confirmed. How do you show that?

4/

Some now use purple for these cases, and others have gone to using purple for all tornado warnings (as well as some others alerts like extreme wind).

But we've got a problem - we've got research showing people don't see purple as bad or worse than red.

Uh oh.

5/

For example, Blink et al. found people made more errors interpreting a graphic whose scale included purple than those interpreting graphics that stuck to yellow/orange/red. The purple group also took longer to process and interpret, even when they got it right.

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Ernst et al. (2021) found that only 11% of respondents — eleven percent! — could correctly order a five-color scheme with green, yellow, orange, red, and purple, with the vast majority not putting purple in the highest slot.

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In a talk-aloud study, where Sutton and Fischer (2021) asked folks to talk through their thoughts as they looked at colors, folks told them purple just doesn't seem like a big deal — and certainly not "worse than red".

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In other words, we are trying to use purple to communicate more urgency than red, but that message is not getting across to our users. It's not their fault! Intuitively (in the west, anyway) red is the high end of the spectrum.

There's no such thing as a purple stoplight.

9/

And that's the corner we've painted ourselves into. We used to use red for the worst thing, but now we've got "worser" things we need to communicate to people.

We can't simply pick another color - even if we ourselves might like it and how it looks.

10/

So, what do we do?

We need to back off using purple as a "worse than red" color, especially in short-fuse warning situations. Folks simply don't intuitively make that connection.

Stick with red but enhance it somehow - blink, shimmer, textures, etc. to help it stand out.

11/

If we must use purple — and I suggest we shouldn't for all the reasons above and more — we need to acknowledge, accept, and follow through in the burden of educating our end users on what that means, being aware that we are fighting against the stream.

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I'm not at all mad or trying to throw shade at anyone who's used purple in these situations. We're all trying our best to communicate life-saving messages to our viewers/followers/users, and we're all learning as we go.

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However, thanks to ongoing efforts to integrate social science with meteorology, we not only have research about color that's on point, it's research that's actually been done in our field. Wow! We should rely on it and let it help guide how we work going forward.

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If you're around #NWAS22 this week (or you're on Twitter and following this conversation) and want to chat, I'd love to discuss this further with you, especially if you have other ideas on how we can use colors to communicate urgent, life-threatening situations.

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Thanks for reading and considering these thoughts. And thanks to @suttonj @LauraMockWX @mmcclellanwx @Sean_Ernst_Wx and others for doing this fascinating research and to @CommDocPA, @jamesaydelott and @BryanBusbyKMBC for the conversations to help me think out loud.

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