fˈɜːst sˈiːn ɪn wˈʌn θˈaʊzənd ˈeɪthˈʌndɹɪd ˈeɪɾi fˈaɪv, tˈuː jˈɪɹz ˈæftɚ ðə pˈaʊɚfəl ɪɹˈʌpʃən ʌvðɪ ɪndoʊnˈiːʒən vɑːlkˈeɪnoʊ kɹˌækɐtˈoʊə, sˈaɪəntɪsts ɚɹˈɪdʒɪnəli θˈɔːt pˌiːˌɛmsˈiːz fˈɔːɹmd fɹʌmðə plˈuːmz ʌv ˈæʃ pɹəpˈɛld ˌɪntʊ ðə skˈaɪ dˈʊɹɹɪŋ ðæt ɪɹˈʌpʃən.
First seen in 1885, two years after the powerful eruption of the Indonesian volcano Krakatoa, scientists originally thought PMC's formed from the plumes of ash propelled into the sky during that eruption.