I believe you mean 'current'. I've seen people use the singular form when they're actually experiencing it in person- when they're flying or sailing. In news reports, however, the plural form is common. Don't know why exactly. This ambiguity does not exist in context of electricity.
I too was irked by getting dinged for "trend" so it's good to know that "tendencia" is preferable. The Chicago dictionary does not list corriente=trend, and I think the problem is the old one of a lack of context. Duo seems to think only currents can be strong, not trends. More context, please, Duo!
without know if the speaker is naturalist talking about the ocean or a fashion critic talking about yes, fashions, how are we to know which translation of "corrientes" is correct as the dictionary has both "currents" and "trends" as probable translations. Have I misread this?